"It's chaos outside. I don't think many are going to work even if they know where to go. They are too worried to leave home, looking after relatives and friends, defending their homes against mobs of looters. Pathetic really. I came across a hoody teenager carrying a huge holoscreen, crying his eyes out. When I asked, he said he couldn't remember where his apartment was.

"There have been fatalities caused by ARIA. Patients forgetting, or their nurses forgetting, to administer medication. Fresh blood and plasma supplies have dried up-oh, badly put, but you know what I mean. So the transplant and by-pass ops aren't happening. I've heard of long-haul plane crashes but that could be rumour. I'm going to risk it anyway. The TV news is spasmodic-but you must know that from Internet TV. Hope it dies out soon before we all return to Neanderthal behaviour, if we survive that long. I've set this on a timer to run on batteries for this uplink in case the mains power is off as it often is.

"When I can, I'll link up to your website, Ryder, and keep my mobile phone charged-but that depends on the service provider still operating. I'm flying to some of my family in Europe. I have the tickets and written flight numbers on my arm.

"Look after yourselves. Oh, get some Huperzine-A patches, although you might need a hospital pharmacy for that. I love you all. Ciao."

Her tearful face faded out, leaving the group watching an empty lab.

"Momentous and yet she didn't realize it," Ryder said.

Teresa said, "She's identified the virus, quasi-virus, whatever anyone wants to call it." Ryder saw tears in her eyes, but she waved him away.

"It should be called the Julia Tynwald Virus," Ryder said.

"Tynwald's ARIA," Derek said. "Sounds like a Wagner opera."

Ryder looked at his mobile phone for the hundredth time as he sent and checked for messages from Karen.

"There's been the occasional message," he said. "But apart from a couple of 'Hi' and 'Okay,' they've just been spurious characters as though she's lost her mobile and using something from another network with compatibility problems. She said she's coming to Europe. One of thousands trying to escape their situation but only to spread it."

Derek pointed at the screen. "Anybody know what Hyper-whatsit is?"

Teresa wiped her eyes with a tissue. "Huperzine-A is an enzyme inhibitor. Our brain needs acetylcholine for thoughts and memory. But there is an enzyme whose job is to make sure we don't produce too much. One theory is that Alzheimer's is the result of that enzyme attacking too much acetylcholine and so affecting memory. Patients taking Huperzine-A usually find their memory and thinking improves."

Derek's face brightened. "I've been taking gingko biloba for years. I should have been dosing up on Hup-A."

"Gingko is good for memory too, although the jury is out on whether it improves brain function."

"Do we need to raid a chemist?" asked Ryder, worrying about contacting people again.

"I don't know. Hup-A is available over the counter in some places. It's an herbal extract, not a commercially processed substance. We might even have some here, we do get visiting students and lecturers who are really into naturopathic remedies."

Ryder shook his head. "In these weird circumstances, we don't know how ARIA is affecting the brain. Maybe it's enhancing this bad enzyme so it's depleting the acetylcholine, causing short circuits in the brain, leading to memory loss. I would think taking anything that might help inhibit ARIA is a good thing."

"It might make it worse," said Teresa, reading through the text that came with Julia's message. "All we know from Julia is that people infected with the virus lose memory function in such a way it spreads, taking out memory in a retrograde fashion. And this is so odd because we don't consider memories to be well organised. We remember odd events and every time you think about them, the acetylcholine for those neurons increases, making it easier to recall them. This illness takes out memory going steadily back in time. Of course, some chunks of memory link to others but not usually for what happened the previous day or week. The loss of memory with Alzheimer's is more random and slow. Some people forget childhood things one week then vocabulary learned more recently the next."

"At least it's comforting some people are working on it," said Laurette. "Hopefully, they can transmit results and ideas before they become too disorganised."

"Good point," Gustav said. "Can we set up a link to the labs at Schenectady?"

"I can try," Derek said, settling to the task.

TERESA AND LAURETTE HUDDLED IN A CORNER with Gustav to summarise the biological aspects of the communication. Ryder tried to follow Derek's expert fingers dancing over the keyboard when the speaker shouted, "Intruder!"

Everyone stared at Derek.

"It might be a glitch," he said. "I've only set up a few sensors and haven't tested it all yet."

"Can't you tell which beam has been broken?" Ryder said.

"It's the farthest gate on the lane, but it should be padlocked. Brian?"

"Ah, it will be tomorrow. I forgot to take it with me when I took the fencing and spike-wired the top rail. Er, sorry, but shouldn't the camera show us-oops, it's dark, isn't it?"

"It'll be doubled up with an infrared cam tomorrow."

"So, the gate is open now?" asked Teresa.

"Not according to the sensor, and sheep don't usually shut gates after them," said Derek. "Either there's a glitch or someone opened then shut the gate."

Laurette ran to a drawer, brought out two of the competition handguns and offered one to Ryder.

"Ammo," Ryder said.

"They're kept loaded," Laurette said. "Not much use in an emergency otherwise."

"Good point," he said.

Brian took a rifle, checked it and strode to the door leading to the refectory.

Ryder liked the solid metallic feel of the Colt 1911, admired the perfect balance yet hated the need for handling it. They all gathered behind the door.

Five minutes later, Bronwyn spoke. "Just a frigging minute. I'm in the Territorial Army, and it's as clear as jelly none of you have had any training. Gustav, take a rifle and aim it at the door from behind that easy chair. Laurette and Derek, take your weapons out the back way and do a cautious reconnaissance. Brian and I know the layout best, so I'll open the door to the refectory but stay against the wall on this side while Brian goes in at a crouch. Ryder and Teresa, also aim at the door but stay behind furniture like Gustav. On the count of three-counting down from three. Right?"

Everybody said yes-even Brian.

Bronwyn said, "Three, two, one, go."

Standing back against the wall to the right of the swing door, Bronwyn eased it open with her right hand allowing Brian, with rifle levelled, to crouch and enter.

"Bloody hell."

"Hi, Uncle Brian," said a young woman.

Brian returned and closed the door behind him.

"It's my brother's daughter. Should I just tell her to go away? Only, suppose she's infected?"

Teresa, with hands on hips, "Which would mean you are probably infected, which means..."

"Ah."

Bronwyn rushed into the refectory. "Megan. My God, girl, what are you doing here?"

Apart from Derek and Gustav on patrol, they all gathered around the young teenager sitting at a table.

"I'd like a jam butty. And how are you, Auntie Bronwyn?"

"I'm having kittens but never mind me. Why aren't you at home?"

"Mum and Dad went Wednesday to the rugby in London and haven't come back. They use any excuse to have a few days in a nice hotel."

"You should've gone to one of your friends, love."

"But you said I was always welcome here, especially when you didn't have a load of students in."

Bronwyn turned to Ryder. "She's right."

A burst of noise entered the front door followed by Derek shouting. "We've found a bike leaning against the wa-oh. Hello?"

Sunday 3 May 2015:.

The Rocky Mountains. Seventeen days since amnesia started spreading. Most people have lost two years and three weeks' memory.

MANUEL DRAGGED HIMSELF OUT OF A DEEP SLEEP. He'd have to get a new alarm clock, because he couldn't stand the racket this one made. His eyes blinked open to stare at a varnished pinewood ceiling. He had a plain white ceiling at home so maybe he'd got lucky, at last. His hand reached out but found empty sheets. So, not that lucky. He levered himself up on his elbows, but his head hurt so he lay back down. The unfamiliar log cabin troubled him even though whispers of deja vu flitted around his foggy head.

He worked hard to focus through the window at a magnificent snow-capped mountain across a lake. Two mountains, if he counted the perfect reflection. Re-focussing, he admired the huge white pine tree outside his window. It wore a pale grey bark, almost silver, oozing strength and fortitude, and it soared above the eaves of the cabin.

"I'm not at home in Baltimore, then," he sighed.

The alarm restarted. He realized the perpetrator liked beetles for its breakfast, and Manuel drew significant pleasure, when he raised himself again, to watch the vermillion-crested black woodpecker send vibrations through the tree.

After a few minutes, reality nagged at him.

"Where the hell am I?"

He staggered to the bathroom, then found the kitchen and prepared coffee and toast. A NoteCom lay on the table. Feeling the coffee wake up parts the shower couldn't, he tapped at the key to reveal a message: You are Manuel Gomez, employed by NASA as their Education Officer for flight missions with responsibility to liaise with the media.

Except you are on leave along with most of the population because you have ARIA, an infectious amnesia deleting your memories at the rate of 50 days' worth each day. This probably started for you on the 15th April 2015. It is now Sunday 3rd May 2015 so you have lost 900 days or two years five months and twenty days of memory.

Hit the ARCHIVE button for your potted bio and relevant addresses and details.

Hit the WHO button for names, addresses, and numbers of friends and colleagues.

Hit the CALL button within WHO to contact people in the list.

Hit the NOTES button for information you have added.

Hit the HELP button for details about this NoteCom and how to make it online to the web.

Warning: some of the information may be out of date.

Don't lose this NoteCom.

Have a good day. Although the information was new to him, and shocking, he realized that every day for months he must have sat somewhere and read the same message. Maybe in this cabin.

Did he recall his father bringing him camping here? No, not his father-his parents lived in Spain. That was it, he'd won a Young Space Journalist fortnight and part of the prize meant a weekend camp in the wilds of Lake Moraine, Banff National Park in Canada. Before he lost all his wherewithal, he must have brought himself back here. Remembered how remote this area was. No smooth-surfaced promenade walks around tarted-up holiday homes like around Lake Louise. Good to get somewhere far from people. Not too long though, he might have a lot of provisions, but they wouldn't be infinite, and backwoodsman skills were not his strong point.

He decided to check on his stores, wondering if he'd done the old trappers' trick of burying some outside in case the cabin suffered a raid by a bear.

He could survive for months on the basic foods he found, though he already had a yearning to find a damn good restaurant. Suppose he made his way down the track to the road? He must have had a vehicle there and could drive to the nearest town. Maybe he shouldn't. How many times had he debated that?

Midday came, and after a crisp-bread and soup lunch, Manuel decided he needed to find more interesting food. He also had a strong urge to find out how ARIA was affecting folk around here. Maybe it had gone away. What information he gleaned off the web didn't say so.

Grid power didn't work, but electricity flowed from solar cells on the south-facing roof and fed to batteries when not drawn. Even so, he should only use electrical gadgets in the daytime. The news sites carried little information. He had logged on to the web, using the impressive mini-satellite receiver and transmitter on a small pylon he found at the back of the cabin, along with mountains of chopped wood. He must have been bored the last few weeks. There had been general looting and mayhem throughout the country, but he wanted to see for himself how secure his hinterland refuge was.

Manuel threw a rucksack on his back and staggered, knocking over a kitchen chair. He re-packed a waterproof coat, NoteCom, camera-since old habits die hard-dried fruit and nuts, and a flask of coffee. He left the axe and the two-litres bottle of water. He set off down the hill.

Forget-me-nots and bluebells greeted him though he had to watch out for poison ivy scraping his feet at the edges of the track. Here in the forest, life continued as normal. He entertained the wild thought that only sentient beings would know they were losing memory. But then only humans had sufficient conscious thought to notice their failing memory. Dogs would forget where they lived, but many did anyway. Looking up at a lodgepole pine, he wondered if trees had memory. He knew they had DNA and everyone knew about tree rings that enabled a tree to remember the wet and dry, cold and hot years. But that lodgepole pine didn't depend on tapping into its tree rings to know where to go home at night. He peered into the darkness beyond the first few trees, looking for bears watching him. National park areas up in bear country were closed in winter. That should include his cabin, yet according to the NoteCom, he'd been there since April.

He heard a coyote off up through the trees to his left. No worries there unless it was warning its family of a black bear. He didn't fancy the idea of running hard. On the other hand, he was fitter than he remembered. Still stocky, but he'd been pulling up his forty-inch trousers. Maybe all that chopping wood and unexciting staple foods turned some flab into babe-magnet material. As if.

After half an hour of steady downhill stepping around muddy quagmires, he came to a hard-surfaced road. A Dodge 4x4 pickup waited there. Dark brown and tan, it had the registration plate the NoteCom told him it should. There, under the rear nearside mudguard hung the keys. He walked around the vehicle looking for any history: deep scratches, dents, or body parts in the front grill, but all he found was a rock wedging a wheel. The rear of the pickup held a chain, rope, tool bag, and tarpaulin, nothing out of the ordinary.

Careful not to set off an alarm, he bleeped the key-fob and climbed into the black leather driver's seat. More comfortable than in any of the chairs in the cabin, Manuel explored the glove compartment. Maps and gloves. No weapon. Fair enough, but maybe he should have looked for one at the cabin. A cell phone and charge unit via the cigar-lighter stared at him. He wondered if he should charge his NoteCom and decided he would. He popped a discovered mint sweet into his mouth and appreciated the instant sugar boost.

Fuel showed half a tank. Plenty for a twenty-mile return trip to the town of Louise Lake. Manuel switched on. Then again. A third time for it to catch and he revved. After a few moments, it purred like a contented mountain lion. He didn't want to attract the attention of any rangers or wild men of the forest. It would be possible for loners to be uncontaminated out here and assume his transgression into their domain needed sorting. Then he didn't want to attract the real wild life either. He moved off, concentrating so as to keep his speed beneath the 80 kph speed limit, but he couldn't help smiling at the "Grizzly Crossing" signs.

The snow lay on the road like icing on a Christmas cake. A few soft blue indentations gave away the night-time trespass of foxes or coyotes but nothing larger.

Manuel's driving would have attracted the attention of traffic police with his meanderings. He couldn't take his eyes off the mountains reaching skywards on the other side of the lake. He allowed his trashed recent memory to remain forgotten to encourage his soul to soar upwards to the summits. Then there was the glow he acquired from driving over virgin snow and the crunching noise from the tyres. Yet another sweep around a bend and he had to brake hard. The wheels stopped rotating but the pickup travelled another ten metres, the hood colliding with the wooden barrier across the road. The impact shattered the padlock. The gate swung outwards to allow Manuel to pass through and right onto the Lake Louise turning.

This road had compressed dirtier snow but no vehicles to cause him panic. He slowed as he crossed the bridge over the ice-blue waters of the Bow River and across the Canadian Pacific Railway line. He glanced up and down the snow-covered tracks.

Manuel turned into the near-empty parking lot of a shopping mall. He stayed in the Dodge surveying the scene, waiting to see if anyone showed up. One minute passed then five. A dark figure emerged from the entrance of the mall. Male, dressed in a long, hooded coat, he staggered to an old Ford truck. With a wry smile, Manuel watched the drunk climb into his vehicle, which coughed away down the road. Had the drunk bought his goods the old-fashioned way, with money in the shops?

A minute later, a transit van drove by him and on to the mall entrance. Three youths and a girl in an oversized white quilted coat tumbled out and into the mall. Happy enough, they behaved like normal idiot teenagers. Manuel guessed he ought to hang on a while. He couldn't imagine the shopping mall would be open and carrying on its retail and entertainment services as normal. No doubt those youths were looting the pharmacy and grocery store. If he showed, they'd either run away, or at him. He wondered if they had their memory intact. Suppose they'd been at a residential college or camp. It must happen. But then it would have only taken one infected cook to arrive and bingo.

Another few minutes and he parked away from the transit, twenty metres from the entrance with no one in front. His intention was to minimise attention by not parking too close yet making it possible for him to make a quick getaway. Pity he had no firearm. Manuel tightened his rucksack to make stealing it difficult and to protect his back. He crept into the mall, keeping to the right edge made of a large smoked-glass, curved wall. It looked as dark as a cave in there. No electricity. The power in the region came from hydroelectric dams in the mountains but still needed people to control it. It reminded him to look for batteries as well as vitamins and food.

Manuel's nervousness began a debate. Did he need luxury foods like chocolate, biscuits, and English tea when he had the basics to survive in the cabin? He could be jumped or chased. He might be slimmer but would only be able to run as fast as a table. The marble-effect floor, carpeted with discarded boxes, clothes, and drinks bottles, led him past looted clothes shops and cafeterias. He ventured down into the gloom. He shivered, out of fear but also, the retail-cave coldness got to him.

An unrolled bandage led him to the remains of a drugstore. Tablets, sweet-yet-pungent goo, and packaging littered the floor. A small seating area had cola drinks with straws on some tables and mouldy sandwiches. The lights had gone out, ending normality in this place in an instant. Most of the shelves had been cleared, but he salvaged some multi-vitamins and diabetic confectionary. The ordinary sugar-laden stuff had gone. Good, he found a torch and spare batteries. On his way out, he passed a full cabinet of natural remedies. None of the looters valued them, but Manuel helped himself to an assortment and a booklet or two. Now, he could find out how to keep his bowels active, his skin clear and he discovered an apt one on Alzheimer's. Another cabinet had held frozen foods. The ice-creams were a collage of swirls and pretty colours. He heard a scratching noise that sent him into a nervous crouch. More scratching and scuffling came from behind an open door leading to the rear of the store. Maybe the shopkeeper had been tied up, came to, and now tried to get away. Still crouching, he used the torch to open the door wider. A mad scramble of scratching and squeals accompanied two rats running through his legs to the main corridor. Manuel laughed and then stopped.

He heard other noises from deeper in the complex. He switched off the torch and concentrated. He couldn't make out the words, but shouting and fighting sounds reached him. Should he hide in the storeroom of the shop until the looters passed? Suppose they lived there and were defending their territory? There'd be plenty of provisions in the supermarket deeper inside. He waited, but the cacophony of the altercation rose and fell in greater frequency. He decided he ought to be satisfied with his minor haul and escape. Creeping to where the drugstore intersected with the main mall corridor, he waited to hear if the voices increased or diminished.

A woman screamed out of sight, deep in the gloom. The primeval sound made hairs prickle on the back of Manuel's neck. Then he heard heavy running coming his way accompanied by the woman shouting, "I'll die, you bastard. Give it back."

The running steps closed in to where Manuel crouched. He stuck out his foot and the runner fell. Jumping, Manuel landed on top of a dirty tweed coat that had held together a bony, bearded man with long, greasy hair. The man gasped as he fought for air and tried to push Manuel off him. It must have been all that chopping wood he couldn't remember doing, but Manuel overcame the odious heap with ease.

"Thanks, I just want my bag back, mister," said the woman wearing the white quilt he saw earlier. She'd caught up during the fracas.

The noxious man grunted, threw away a holdall, and struggled away on all fours. Manuel let him go while the woman grabbed her bag. He turned to talk to the woman, but she had gone after the still-crawling man.

"I wouldn't if I were you," Manuel called, but the woman took no notice and gave the man a vicious kick in the ribs, making him roll over. He grunted, grabbing at his side while she kicked him again in the balls. Manuel pulled her away, but she shook him off. More shouts could be heard from inside the mall.

"You got transport?" she asked. He studied her white, young face for the first time. She looked fourteen.