The stranger turned round sharply. 'What's more important is that somebody seems to be operating a source of detectable temporal interference in your city.'

Li nodded towards a pair of his men who were restraining a tall dark-haired western woman in a red dress. 'You're the only ones I've seen interfering in anything.' Li beckoned to his men. 'Take these two back to the station for questioning.'

Five.

The police station's main office was half empty and as colourless as

the grey streets outside. As with those streets, though, there were plenty of posters and banners on the walls. The woman sat down wearily, while the man slouched into a chair and casually put his feet up on Li's immaculately neat desk. Li knocked them off with a rap from a ruler and sat down in front of his typewriter. He still smarted from losing the woman and was in an uncharacteristically vindictive mood which belied his open and friendly visage.

'Let's start with your names.'

'Well, I am the Doctor and this is Romana. We're just sort of pa.s.sing through Shanghai, in a very temporal sense.'

'Your real names?'

'I'm not sure I could remember it, offhand.'

Li didn't find the man's att.i.tude amusing. A Chinese prisoner would never be so foolish. 'Don't tell me you're going to plead amnesia?'

'No, it's just been so long since I last used it. Besides, names have power, Sung-Chi Li.'

Li started, but hastily composed himself. 'How do you know that?'

'You signed the charge sheet in front of you.'

'Most gwai lo gwai lo can't read Chinese script.' can't read Chinese script.'

'Well, I've been around a bit, you know Gwai lo Gwai lo... ghost man? I admit I've died a couple of times, but it doesn't look that serious, does it?'

Li was beginning to feel all too scrutable. 'Third time lucky?'

The Doctor grinned cheekily. 'I suppose it was.'

'Names?'

'Just put Doctor John Smith.' He looked at Romana with a shrug. 'I didn't choose it.'

Li glared at him suspiciously, half-expecting another correction, but none came. He wrote the name down, reflecting that the Doctor's childish attempts to put him off were almost certainly proof of guilt. The firing squad would have something to look forward to. 'And your full name?' he asked Romana.

Romana's mouth quirked upwards.

'Romanadvoratrelundar.'

'It's Polish,' the Doctor supplied helpfully.

'All right, now to business. What is your connection to the woman who was at the docks?'

'None, of course. We've only just arrived in the city.'

'So has she, as far as I know. Try again.'

'What possible reason could you have for thinking that we '

'She seemed to recognize you, for one thing. And you did let her get away from me.'

The Doctor's expression darkened. 'Shooting unarmed women in the back is not what I'd call justice. I mean, what happened to all the processes you're supposed to go through first, eh? "Freeze. Stop or I shoot." Complex legal jargon like that.'

Romana nodded. 'How were we supposed to know you were policemen? You weren't in uniform.'

Li was tired and not really up to debating with the prisoners. As for their questions as to procedure, he found that gravely insulting. He had followed the regulations thoroughly.

'All right, if that's how you want to play it.' He beckoned to a uniformed officer near by. 'Empty their pockets and lock them up. They might be more talkative after a few hours with the other rats.'

The Doctor leaned forward to fix Li with a penetrating glare as the uniformed officer grabbed his arm. 'You're making a very big mistake, Inspector; someone is misusing energies that could blow this city halfway to Mars, and we're the only ones who might be able to help.'

'If you want to help, then start telling the truth.' Li waved and the uniformed officer dragged the Doctor off to the cell area. Romana went rather more quietly, Li was gratified to note, though she maintained her bearing. It was as if she were going along purely as a favour.

Li let himself relax once they were gone. The lengths some people would go to to avoid conviction were amusing. No doubt he would have to try to find out from the Settlement Police who these two really were. Li had been the eldest of seven children and became man of the house when his father died in the 1911 revolution that overthrew Pu Yi. He hadn't been killed by loyalists or rebels, but crushed in a crowd cheering a visit by Sun Yat Sen. Li had quickly found that to maintain the family, discipline was needed, and this was something he had always found in everything he had done since.

The Doctor fell to the floor as he was shoved into a stone-walled cell opposite Romana's, but wasn't getting any sympathy from the policeman on guard who slammed the door, slid the locking bar across and left the cell area. Romana tapped her solid door experimentally. 'Locked with a wooden slide? Do they still use such primitive technology here?'

'Primitive but effective: no circuitry to disrupt, not even a metal bolt susceptible to a magnet. Even the sonic screwdriver won't get us out of this one...' He held up a dog whistle. 'This should, though.'

'K9? Will he be able to make it through the city? He will stand out a bit.'

'Of course he'll make it. He's the only dog in the country that won't have to run from any chefs.'

It had been a long night and Li had never actually got to bed, so he felt fuzzy from lack of sleep. He was beginning to wonder whether his family even recalled his name, so infrequently did they actually see each other these days. Still, he had some leave coming up soon, so he would make it up to his wife for being absent so often.

There was a note beside his little cup of joss sticks on his desk, informing him that the forensic team had finished with both the body and the knife. Fortune smiled on him, it would appear. Fetching a cup of tea from a battered office urn, Li grabbed his case notes and headed down to forensics in the bas.e.m.e.nt.

Professor Ying was doing some paperwork, while his a.s.sistants mopped around the wooden examination tables in the drab brick room. The aloof features that surrounded his moustache neatly trimmed in European style shifted into an acknowledging look as Li wandered in.

Li sometimes thought Ying had it easy; even the dead were all cleaned up in here and not lying amongst the rats as he usually found them, but admittedly some scientific expertise was occasionally useful. It was not what he'd call policework or crime-fighting, though. Even Yan Cheh's interference was more comprehensible to Li. 'You have something for me?'

Ying nodded gracefully. 'Your dead Englishman was killed by a single knife thrust to the heart from directly in front.' He checked his notes. 'The knife went in at a sixty-degree upward angle under the sternum.'

Li had already judged as much. 'What about the knife with the blood?'

'The only fingerprints on the knife are those of your prisoner. We also found his palmprint on the door and bonnet of the abandoned car at Nang Tao. There were bloodstains on the car which match both those on the knife and the blood of the body.'

Li nodded, satisfied. 'Then we can prepare an arraignment immediately.'

Ying smiled lopsidedly. 'There is a problem.'

'What?'

'The knife doesn't appear to be the murder weapon. The weapon used on the body had a blade approximately twice as wide as this one.'

'Couldn't it have been...?' Li made a see-saw motion by way of demonstration.

Ying shook his head. 'Wiggling it to enlarge the wound would show. I suppose it's theoretically possible that a second, larger, knife was used to disguise the state of the wound after death. I can't see why, though.'

'You're telling me I need to look for a second knife?'

'Or an accomplice.'

That woman Romana, Li thought; perhaps she was more deeply involved than he had thought. 'I'll bear that in mind. I think I have another interrogation to conduct.'

Yeung had watched the new arrivals from his cell, wondering what they had done to get locked up in here. Westerners usually had their own laws.

The Doctor had stuck his arm out between the bars in his door and was aiming a loop of his scarf at the handgrip of the locking bar. Romana watched with obvious interest from her cell opposite. 'So that's what that's for...'

'Yes...Well, it is today, anyway.' With a flick of the wrist, he shot the woollen loop out, and it wrapped itself around the handgrip. 'Aha! I should be a rancher in the Old West.' He drew his hand back in through the bars and looped the scarf around the one furthest from the handgrip. Carefully, so as not to break the wool, he pulled back on it. The scarf dragged the locking bar along until it was free of the door. Grinning, he opened the door and stepped across to Romana's cell to open it. Yeung was astounded; this gwai lo gwai lo was much better than the late Liu. A chorus of pleading cries started up from the other cells. was much better than the late Liu. A chorus of pleading cries started up from the other cells.

Romana stepped out of her cell like an empress emerging from a sedan chair. She looked grudgingly impressed. 'That was very practised.'

'You get locked up a lot in this sort of job.' The Doctor settled the scarf back on his shoulders. 'It's definitely time we weren't h' A sudden harsh burst of crackling interrupted him.

Romana started visibly and pulled a wand from its hiding-place up her sleeve. 'It's picking up something very close, too, by the sound of it.'

'What, just like that? If it is the fourth segment, then where has it been all this time?'

Romana pointed the tracer into various corners of the cell block before directing it down past the row of cells. It responded even more strongly. 'It seems to be coming from the end of the corridor.' Her eyes suddenly widened in surprise. 'Doctor, look!'

Yeung craned his neck to look as well and soon wished he hadn't. Yan Cheh's accursed skills were as nothing compared to this. A rippling pattern of light was coalescing across the stonework; imploding ripples like a splash in reverse. The pattern soon shifted to a more bipedal shape, and before any of them realized what was happening, a man in loose black clothing had stepped out of the wall. The occupants of the other cells immediately fell silent with indrawn gasps.

Three more similarly clad men stepped out of the wall beside the leader as he looked around, then at the Doctor and Romana. They were all armed: the first with a curved broadsword, the others with a pair of b.u.t.terfly knives, nunchaku nunchaku and a vicious-looking hatchet. and a vicious-looking hatchet.

The Doctor cleared his throat self-consciously and stepped forward. 'Ah, how do you do? I'm the Doctor, and this is '

He ducked as the curved sword blade flashed past his head.

Romana backed towards the door to the main part of the police station and tried the handle. It was locked.

The a.s.sa.s.sin with the hatchet hurled it at her. She ducked and it whirred through the bars in the door and thudded into something in the main office. Cries of alarm rose from the office and there was the sound of running feet and jangling keys.

The Doctor hurled a wide loop of his scarf over the swordsman's head and tugged backwards, overbalancing him.

The knifeman immediately tripped over him. Three policemen burst into the corridor from the main office and waded in with a flurry of blows from their truncheons, but seemed as intent on defeating the Doctor as they were on defeating the a.s.sa.s.sins.

Romana slipped out into the office as the Doctor threw himself to the floor in an effort to avoid being sandwiched between the struggling combatants. She had scarcely vanished from Yeung's view, when a mechanical beast trundled into the corridor. Yeung pressed himself back against the wall of his cell. Human opponents were one thing, but this was surely demonic. 'K9,' the Doctor called, trying to keep the nunchaku nunchaku safely tangled in his scarf, 'stun them!' safely tangled in his scarf, 'stun them!'

K9 responded immediately, with a rapid volley of red lightning blasts. The policemen and a.s.sa.s.sins all tumbled in a shapeless heap and the Doctor pulled himself from under the pile of bodies with difficulty. He dusted himself off. 'Your sense of timing leaves something to be desired.'

K9's tail drooped slightly. Romana shook her head as she returned. 'I don't think you're being fair on him, Doctor.

Better late than never.'

'It's the possibility of being "late" that bothers me. Help me get them into these cells.' He started dragging an a.s.sa.s.sin into his own erstwhile cell, while Romana started depositing the policemen in hers. Although the Doctor had less difficulty moving his charges, Romana had one man fewer to deal with, and so they were finished at the same time. The Doctor knelt to examine the unconscious a.s.sa.s.sins with a frown. 'Romana, look at this.'

Romana locked the door of her cell and joined the Doctor in his a.s.sa.s.sin-filled one. 'What is it?'

Yeung could see that the Doctor had pulled a small silver locket from around one man's neck. 'This is odd; none of them have any identification, but they all have one of these lockets.'

Romana lifted the locket from the a.s.sa.s.sin nearest to her. It was a plain and uninscribed circular locket. She opened it.

'There's some sort of inlaid ceramic inside.'

The Doctor looked in the locket he had picked up. Set into it was a ceramic compa.s.s made up of seven turnable concentric rings with a compa.s.s needle in the centre. Each of the five outer rings was divided into sections, with each section containing a character of Chinese script. The sixth ring was divided up into areas containing combinations of dots, while the innermost ring was annotated with eight symbols from the I Ching I Ching. All of the hand-inked symbols were in the same shade of burnt red. 'Peculiar.'

'It looks like some sort of compa.s.s, or measuring device.

For map-making?'

The Doctor shook his head. 'It's a geomantic compa.s.s, used for determining positions that have good or bad luck. I've never seen one with movable parts before, though.'

Romana traced a finger across the face of the geomantic compa.s.s she held. 'Presumably the compa.s.s point tells you where you are in relation to the planet's magnetic pole and also points to the symbols telling you good or bad fortunes.'

She gave the unconscious man a very disapproving look.

'Something like that.'

'It's all superst.i.tious nonsense, of course.'

'Superst.i.tion can be useful. I once walked under a ladder and...' He shook his head sorrowfully.

Yeung saw Romana was curious in spite of herself. He had to admit that leaving a tale unfinished like that was frustrating.

'Well?' Romana urged. 'What happened?'

'The signwriter whose ladder it was dropped his paint. It took three days to wash it all out.'