"Okay, but, um, well, can I come too?" she said, remembering Tess's stipulation.

Louis seemed slightly taken aback. "Why? I mean, that's great, I'd like you to come along, but I'm not planning to smuggle them abroad or anything."

Sophie nodded. "I know that, but they don't know you, do they?" She shrugged. "Look, I'm sorry, but Tess told me I should stay with them for the first few visits. If you don't like it, you'd better call her."

Louis sighed. "No, no," he said. "If that's what Tess wants. Right then." He winked at Izzy. "Want to go to the zoo, Izzy?"

"Yes, I do, I do want to go to the zoo! I want to see the penguins and the spiders," Izzy shouted, her new hat jammed on her head, the mittens flailing off the sides like demented antlers. Louis and Izzy laughed together, their eyes dancing.

"I'm not going," Bella said flatly, without taking her eyes off the TV.

"You are going," Izzy said. "You're coming with me and the man who is my daddy to the zoo to see penguins and spiders, aren't you?"

Bella shook her head and glared at Izzy. "I am not," she said emphatically.

Sophie saw Izzy's lip begin to quiver and quickly knelt beside her. "It's okay, darling," she said, putting an arm around Izzy. "Hang on a minute." She gave Izzy a squeeze and walked the short distance over to Bella on her knees. "Bella, I know this is hard for you, but please don't make it hard for Izzy too. She wants to go to the zoo. And I bet you do too, really, don't you? I'll be there, and if you don't go, none of us will." Bella stared blankly at her.

Izzy came over and put her hand on Bella's knee. She was sobbing, deep, dry, ragged breaths that sounded painful. "Please, Bella," she begged. "Be happy!"

"Come on, Bella," Sophie said. "Show Izzy what a grown-up big sister you can be."

Bella sighed and looked at Sophie. "I am only six, you know," she said glumly, and Sophie felt terrible.

"I know," she said. "I keep forgetting you are such a little girl because you are so clever."

"Okay, I'll come to the zoo, I suppose. But I shan't enjoy it," Bella said reluctantly.

Eighteen.

There was a debate about how to get there. Probably in an early attempt to scupper the whole expedition, Bella had refused to go on the bus because "buses smelled." At first Izzy had seemed quite happy to go in Phoebe-partly because of Sophie's "therapy" but especially because Sophie had bought a booster car seat for each child and a cat-shaped sunscreen for each girl's window despite the now total absence of sun-but as soon as they reached the end of the road and turned left instead of right and she realized that taking their usual route around the block would not get them to the zoo Izzy started crying and quickly became hysterical. "No no NO NO NO NO NO!" she screamed. "GET OUT GET OUT GET OUT."

"My God," Louis said, alarmed, twisting around in his seat. "Shhh, Izzy, it's okay, it's okay. Stop the car," he ordered Sophie. "She needs to get out."

"Hang on," Sophie said. "Just wait a minute. Bella, let's sing."

Louis stared at her. "Sing? Look, she's really upset, so just stop the car-"

But Sophie and Bella had already begun to sing their new and constantly revised version of "Motorcycle Emptiness." Louis watched as Izzy's screams gradually subsided into sobs, and as he recognized the song he sat back in his seat, staring straight ahead at the road. Sophie glanced at him. It was hard to tell what he was thinking, but he suddenly looked like he was miles away. By the time she had turned the car back in to her road, Izzy was calm again.

"It's all right now, Izzy," Bella said, helping her sister clamber out of the car onto the pavement before engulfing her in a hug.

"I hadn't realized how traumatized she is by the accident," Louis quietly said to Sophie.

"But, of course, she would be. She was right there in the middle of it." Sophie quickly filled him in on the details of the accident as the girls hugged each other.

"It's really frightened her, hasn't it?"

Sophie nodded but clapped her hands as Izzy and Bella came over. "But we're making progress aren't we, Izzy? We went quite far then and nothing bad happened, did it?" Izzy shook her head and wiped her new mittens across her nose, leaving a trail of mucus shimmering on her cheeks. Sophie took one of the tissues that she had begun to keep always somewhere on her person and mopped up Izzy's face.

"We go a little bit farther every day. I think that today was just a bit too far all at once," Sophie explained to Louis.

"That's a really good idea," he told her.

She smiled at him. "Thanks," she said. "I read about it in a dog training book."

Louis blinked at her. "Right," he said, raising his eyebrows. "Well, I'll say one thing for you, you're full of surprises. Excellent. So what's the new plan?"

"Well," Sophie said. "As Bella is dead set against the bus, there is only one plan left. We take the Tube."

It was an interesting journey to say the least. Izzy became convinced that the Tube trains were fire-breathing dragons. Bella took a seat as far away as possible from Louis, and Sophie, who was concerned that a six-year-old girl should not appear to be alone on the London Underground, sat next to her. At this point, Izzy insisted on sitting on Sophie's lap. So they made the whole trip without exchanging a single word with Louis, although Izzy did occasionally throw him a cheery mittened wave.

And when they emerged at Camden Town Tube station because Regent's Park was closed, it was raining. Louis had thought about hats, but neither he nor Sophie had considered the eventuality of rain, probably rather foolishly, as February was making up for the year's early brightness by becoming the second wettest month in recorded history.

"Let's run!" Louis shouted, grabbing Izzy's hand and heading in the direction indicated by the tourist signpost.

"Um, hang on-" Sophie called out to him in vain. She had wanted to point out that it was actually rather far from Camden Town Tube station to the zoo, but it was too late. She looked at Bella, and joining hands, they ran after him. It took them twenty minutes to get to the zoo's entrance, by which time it had stopped raining, but they were all wet through and out of breath.

"That was pretty far," Louis said to Sophie. "You should have told me."

She bit her tongue and said nothing as he paid the entrance fee.

"Two adults and two kids, please," he told the girl in the booth.

"You save eight pounds with a family ticket, sir," she said, fluttering her lashes at him and dimpling prettily. Louis's brow furrowed, and Sophie worried for a moment that he might be about to point out that they weren't exactly a family. But then the girl asked him for forty-two pounds for a family ticket and he went a shade paler under his Peruvian tan.

"Right, okay," he said. "Um, do you take traveler's checks?"

Sophie knew that she could and possibly should have stepped in with her credit card, but she decided if Louis was serious about being a dad, he needed to know about things like how much it cost to go to the zoo.

"I only wanted to visit the zoo," he muttered to Sophie as they filed through the turnstiles. "Not to buy it."

She smiled at him. "A bit different from Peru, hey?" she said.

Louis gazed down at her. "I'll say," he replied.

Sophie looked at the bedraggled girls. "Let's get a warm drink, and then we can stand under a hand dryer for a few minutes, warm up and dry out a bit before we look at the animals. What do you think?" Sophie looked at the sky. "There's some blue up there now, look."

Izzy nodded. "Mummy made it," she said.

Sophie thought it was only fair that she should pay the 9 million pounds (okay, eight eighty-six) for the three hot chocolates and a coffee, so Louis and Izzy picked which of the many empty tables they wanted to sit at in the Pelican Cafe and Bella came to the cashier with Sophie.

"See," Sophie said. "It's not so bad, is it?"

Bella said nothing but looked over to where Izzy was screaming and giggling as Louis tickled her with her discarded mittens.

"It's good to see Izzy laughing, isn't it?" Sophie tried again as she carefully guided Bella and the tray of hot drinks across the cafe. This time Bella shrugged and mumbled, "She's always laughing." Sophie set the tray down on the table and hung the girls' coats over the backs of their chairs.

"Come on, girls," she said. "Let's see if we can dry off a bit."

Izzy was chattering happily about penguins as she sat on the toilet, and Sophie ruffled Bella's hair under the hand dryer until it was mainly dry once more. As Izzy hopped off the toilet and made a big production of pulling up her tights, she giggled at Bella and said, "It's good to have a daddy, isn't it, Bella? 'Cos now Mummy's gone, Daddy can look after us instead!"

Sophie was completely unprepared for what happened next.

Emitting what Sophie could only describe as a growl, Bella flew at Izzy and pushed her violently. The smaller girl fell hard against the stall partition, banging her head with an audible crack.

"Don't you dare say that!" Bella shouted. "I hate him! I hate him! I HATE HIM!" Izzy was screaming, tears streaming down her frightened-looking face. Sophie grabbed Bella and had to pull her off her sister, putting her arms around Bella to encircle the child's flailing arms.

"Bella!" she found herself shouting. "Calm down now." But Bella did not calm down. Izzy sat screaming on the floor, her arms outstretched to Sophie, desperate to be comforted, and Bella struggled furiously, attempting to break free. For what seemed like the longest time, Sophie thought she would be stuck in the ladies' room at London Zoo forever, caught between the two of them, unable to reach out and comfort Izzy, unable to calm Bella down. Then the door opened and Louis stuck his head in.

"Everything all right in here?" he said. "I thought I heard-" Seeing immediately that it wasn't, Louis came in. "What happened?" he asked.

Sophie shook her head, indicating that now was no time to go into details. "Just take Izzy outside. She banged the back of her head, quite hard I think. You'd better make sure it's not cut," Sophie said over Bella, who was now bright red and sobbing.

Louis reached Izzy in two long strides and scooped her up, but instead of taking her out, as Sophie had requested, he paused by Bella. "Bella, darling..., please-" he began.

"I hate you!" she screamed at him. "Go away, go away, go away!"

Louis froze for a moment and looked at Sophie.

"I think you'd better go," she said, desperately nodding at the door.

At last Louis relented and carried Izzy, sobbing into his chest, back to the cafe.

Hours seemed to pass in the few minutes that Sophie stood there, her arms securing Bella to her body as she waited for her to calm down. Finally she felt Bella's rigid muscles soften, her racing heart slow, and her ragged breaths begin to even out. At last Sophie was able to let her go and turned Bella around to face her, her hands on her shoulders.

"Why did you do that to Izzy?" Sophie asked evenly. She had never seen the girls have a fight any more serious than squabbles over who got the baby doll and who got the felt-tips. And even those they usually resolved between themselves. To see placid, self-contained Bella so out of control was more than a shock to Sophie. It frightened her.

"I don't know," Bella said. "And anyway, she doesn't know anything. They can't make me live with him if I don't want to, can they?"

"No, they can't make you, Bella," Sophie said. "But it's really important that you give him a chance."

"Because you don't want us?" Bella asked accusingly.

"No! It's not that I don't want you-" Sophie stopped herself before she said too much.

"But you said I didn't have to like him-" Bella insisted.

"I know what I said," Sophie said. "But don't stop yourself liking him either. You told me Mummy didn't want you to hate Louis, didn't you?"

"Yes," Bella said reluctantly.

"So why can't you give him a chance and get to know him again?" Sophie asked. "He might be all right." In fact, Sophie thought, so far he had seemed very much all right.

Bella shook her head. "She doesn't know anything," she said, referring to Izzy again. "She's just a baby who wants a nice new daddy. She doesn't even understand what's happened!"

Sophie dropped her head. "That's not true, Bella. Izzy misses your mum. Just as much as you do." She was at a loss for what to say next. "I thought you understood that."

Bella screwed her fists into her eyes, rubbing them vigorously. For once she was looking and acting exactly as young as she was. Sophie crouched down and hugged her.

"Izzy doesn't know him," Bella said. "She doesn't remember him going. I do. And it's not right, it's not right for her to be all happy about him coming back when Mummy can't."

Sophie's mind seemed to go blank; all the words of wisdom she had been plucking out of nowhere recently had deserted her. For what seemed like an eon, she did not know what to say. And then, in the back of her dark, blank mind, she saw a tiny flame of a memory, which she thought she had smothered long ago, begin to flicker and burn brightly.

"My dad died when I was quite young," Sophie told Bella. "I was older than you. I was thirteen, but it was almost the same as it was for you. It wasn't expected. I said good-bye to him one morning as he left for work. By the time I got home from school, he had gone." Bella watched her, with her dry, dark eyes. "I missed him so much, Bella, I didn't want to feel that pain. The only person who made me able to bear it was Carrie, your mum. I couldn't go to my mum because she was as upset as I was. And I didn't have any brothers and sisters. Your mummy was always there for me, to help me through it. Always, forever, whatever-remember?"

Bella nodded, and Sophie felt her thighs cramping, so she sat down on the floor, grateful that the bad weather had kept the ladies' room empty so far. Bella sat down with her. "Your mum helped me, not to forget but to control it." Sophie hesitated. She wasn't sure that this was a memory she wanted to revive. But, she reasoned, look at where burying her pain and memories had got her, a lone cold fish. Bella was only six-you shouldn't have to do that when you were only six.

"Christmas came," Sophie went on. "It was about three months after Dad had died. We went to stay with some cousins of Mum's in Suffolk. She thought it would be for the best, she thought it would be better than her and me looking at each other across the Christmas table on our own. I hated it. I didn't want to go and stay with loads of people I hardly knew. I didn't want to do anything. If I couldn't be with my dad, I wanted to be at home on my own and forget Christmas."

"That's what I wanted too, but we weren't allowed to stay at home either," Bella said.

Sophie nodded. "I know," she said. "But it turned out when we got there that Mum was right. It was good to have some cousins to hang about with, some other things to look at and listen to. I didn't stop missing Dad or hurting, but it helped me to turn it down. Like when you turn the volume down on the telly-do you understand what I mean?" Bella nodded. "And then on Christmas Day we were all sitting around eating lunch, and someone told a joke-I can't even remember what the joke was now, but it made her laugh." Sophie paused as she remembered the moment. "I hadn't seen her smile in three months, but there she was laughing and laughing, for what seemed like forever. I was so angry. I got up and I shouted at her. I said, 'How could you?' I ran out of the room and into the garden so fast that I kicked my chair over and my drink too. I was so angry with her, Bella, because I thought her laughing meant that she had already forgotten Dad."

Sophie bit her lip and, reaching out, brushed a strand of Bella's hair behind her ear. "Mum came out and found me. She knew why I was so cross, and she told me that sometimes you have to practice being happy, even when you're not, because otherwise you might forget how altogether. She said that Dad would want me to be happy whenever I could, that he'd never want me to miss a single chance to laugh because of him." Sophie found herself smiling as she thought of her mum. She had taught her something after all, perhaps even more than she realized, even if it was only now that Sophie finally understood.

"It's easier than you think to let being happy go forever, and once its gone, it's hard to get it back again," Sophie said. "I don't want that to happen to you. Mummy wouldn't want it, and believe me, neither would your daddy. Is that why you pushed Izzy? Were you angry with her for being happy?"

Bella regarded Sophie for a long moment and then, clambering up, put her arms around Sophie's neck and kissed her softly on the cheek. "Yes," she said. She took a breath. "But I know really that Izzy misses Mummy as much as me. I just hate him. He makes me so angry, and I took it out on Izzy. I'm sorry."

Sophie scrambled to her feet. It was pointless to press the girl any further, especially when she felt Bella had just begun to really trust her. And Sophie found that having Bella's trust was an achievement that gave her more satisfaction than everything she had done at the office. Because getting Bella to trust her was far, far more difficult than jumping through hoops to impress Gillian every day.

"I think you'd better tell Izzy that, don't you?" Sophie said, holding a hand out to help Bella up.

They emerged at last from the ladies' room, and Sophie gratefully took a breath of air that was not tinged with disinfectant. Bella and Izzy saw each other across the cafe, and as Bella crossed over to the table, Izzy climbed off Louis's lap and made her way toward her sister. They met halfway and hugged each other tightly.

Sophie stayed a few feet away and looked at Louis over their heads, but he wasn't looking at her. He was looking at his daughters, his face wrought with sorrow.

"We could still go and see the spiders," Sophie said as the girls broke their embrace.

"I want to go home," Izzy said, looking at Bella. "I don't like the zoo anymore. It's stupid, like you said."

"Maybe that would be best," Louis agreed, looking suddenly tired and careworn as he joined the small group with the girls' coats over his arm. "Maybe it was too much too soon. Come on, let's go."

Back at the flat, a little over two hours after they had left it that morning, Bella helped Sophie empty three tins of tomato soup into three bowls and put them in the microwave one by one.

"Right then." Louis appeared in the doorway. "I'll be off."

"Hang on a minute," Sophie said, gesturing that she wanted a word. "Bella, don't touch the microwave when it beeps, okay?" Bella nodded and looked closely at the spoons as her father left.

"So," Louis said as Sophie followed him to the flat door. "Same time tomorrow then?"