Mouse’s father turned and hurried back outside. The woman followed behind.

Mouse watched on silently, staring through the window as her father unloaded bags of the woman’s things from his trunk. So many things, Mouse didn’t know what to make of it all.

When they came back inside, the woman slipped a candy bar out from the inside of her purse and handed it to the girl. Your father says chocolate is your favorite, she said, and it was, second only to Salerno Butter Cookies. But chocolate was a sorry consolation prize for a puppy. She would have rather had a puppy. But she knew better than to say that.

Mouse thought about asking the woman when she was going to leave. But she knew better than to ask that, too, and so she took the candy bar from the woman’s hand. She held it in her sweaty hands, feeling it go limp in her grip as the chocolate started to melt. She didn’t eat it. She wasn’t hungry, though she hadn’t had dinner yet. She had no appetite.

Among the woman’s many belongings was a dog crate. That got the girl’s attention. It was a good-size cage. Right away, Mouse tried to imagine what kind of dog it might hold: a collie or a basset hound or a beagle. She stared out the window as her father continued to bring things in, wondering when the dog would come.

Where’s your dog? the girl asked after her father had finished unloading the car and come back inside, locking up behind himself.

But the woman shook her head and told the girl sadly that she didn’t have a dog anymore, that her dog had just very recently died.

Then why do you have a dog crate? she asked, but her father said, That’s enough, Mouse. Don’t be rude, because they could both see that talking about the dead dog made the woman sad.

Mouse? the woman asked, and if Mouse didn’t know any better, she’d have thought the woman laughed. That’s some nickname for a little girl. But that was all she said. Some nickname. She didn’t say if she liked it or not.

They ate dinner and watched TV from the sofa, but instead of sharing the sofa with her father, as she always did, Mouse sat in a chair on the other side of the room, from which she could hardly see the TV. It didn’t matter anyway; she didn’t like what they were watching. Mouse and her father always watched sports, but instead they had on some show where grown-ups talked too much and said stuff that made the woman and her father laugh, but not Mouse. Mouse didn’t laugh. Because it wasn’t funny.

All the while, the woman sat on the sofa by Mouse’s father instead. When Mouse dared to look over, they were sitting close, holding hands like they had when she first arrived. It made Mouse feel strange inside. She tried not to look, but her eyes kept going back there, to their hands.

When the woman excused herself to go clean up for bed, her father leaned in close and told the girl that it would be nice for her to call this woman Mom. He said he knew it might be strange for a while. That if she didn’t want to, it was okay. But maybe she could work her way up to it in time, her father suggested.

The girl always tried to do everything she could to please her father because she loved him very much. She didn’t want to call this strange woman Mom—not now, not ever—but she knew better than to argue with her father. It would hurt his feelings if she did, and she didn’t ever want to hurt his feelings.

The girl already had a mother, and this was not her.

But if her father wanted her to, she would call his woman Mom. To her face anyway and to her father’s face. But in her own head, she would call this woman Fake Mom. That was what the girl decided.

* * *

Mouse was a smart girl. She liked to read. She knew things that other girls her age didn’t know, like why bananas are curved, and that slugs have four noses, and that the ostrich is the world’s biggest bird.

Mouse loved animals. She always wanted a puppy, but she never got a puppy. Instead she got something else. Because after Fake Mom arrived, her father let her pick out a guinea pig. He did it because he thought it would make her happy.

They went to the pet store together. The minute she laid eyes on her guinea pig, Mouse was in love. It wasn’t the same as a puppy, but it was something special still. Mouse’s father thought that they should name him Bert after his favorite baseball player, Bert Campaneris, and Mouse said yes to that because she didn’t have another name in mind. And because she wanted to make her father happy.

Mouse’s father bought her a book about guinea pigs, too. The night she brought Bert home, Mouse climbed into bed, under the covers, and read the book from end to end. She wanted to be informed. Mouse learned things about guinea pigs that she never knew, like what they eat and what every single squeak and squeal means.

She learned that guinea pigs aren’t related to pigs at all, and they don’t come from the country of Guinea, but from somewhere high in the Andes Mountains, which are in South America. She asked her father for a map, to see where South America was. He dug one out of an old National Geographic magazine in the basement, one that had been Mouse’s grandfather’s magazine. Her father had tried to throw the magazines away when her grandfather died, but Mouse wouldn’t let him. She thought they were fascinating.

Mouse put the map on her bedroom wall with Scotch tape. She stood on her bed and found the Andes Mountains on that map, drew a big circle around them with a purple pen. She pointed at the circle on her map, and told her guinea pig—in his cage on the floor beside her bed—that was where he came from, though she knew her guinea pig hadn’t come from the Andes Mountains at all. He had come from a pet store.

Fake Mom was always calling Bert a pig. Unlike Mouse, she didn’t read the book on guinea pigs. She didn’t understand that Bert was a rodent, not a pig, that he wasn’t even related to pigs. She didn’t know that he only got that name because he squeaked like a pig, and because once upon a time someone thought that he looked like a pig—though he didn’t. Not at all. That someone, in Mouse’s opinion, was wrong.

Mouse stood in the living room and told Fake Mom all that. She didn’t mean to sound like a know-it-all. But Mouse knew a lot of things. She knew big words, and could find faraway places on a map, and could say a few words in French and Chinese. Sometimes she got so excited she couldn’t help sharing it all. Because she didn’t know what a girl her age was supposed to know and not know, and so she just said what she knew.