It’s the sort of Sunday afternoon that makes people abandon their TVs, computers and home-improvement projects to be outside. Protected from the sun by glasses, creams and hats, they flock to pools and beaches; parks and picnic grounds; backyards and decks. Tennis, boating, white-water-rafting, hang-gliding, golf, mountain climbing, abseiling, even weeding; they’ll do anything – as long as they do it under that big blue sky. Music, laughter and the smoke from scores of barbecues fill the air. It seems as if the whole world is out of doors and having a party. Celeste is in her room.

Celeste’s room – or her side of it at least (Astra’s could only be described as a mirror image if the mirror has been shattered into hundreds of pieces) – is organized and tidy, if idiosyncratic – rather like Celeste herself. There is a shelf of books, a shelf of CDs and a small collection of vinyls (given to her by her father). The clothes in her chest of drawers are all neatly folded; the clothes on her side of the closet neatly hung, the shoes underneath them lined up on a metal rack. Each of her knick-knacks has its own place and is regularly dusted. But there are strings of fairy lights around the window and crisscrossing the ceiling over her bed, and the walls are decorated with the framed sheet music of some of her favourite songs rather than the usual posters and prints. The effect is personal and homey (as opposed to Astra’s effect of chaos and destruction). Right now, Celeste is sitting on the floor, playing a song on her guitar. This is how and where she spends most of her free time. Keeping well away from her mother and her sister. She doesn’t feel bad for avoiding her sister – Astra is always in a mood, and it’s rarely a good one. She does have guilt about avoiding her mother, but the truth is that, though this is something she would never say either silently or out loud, she doesn’t always feel like being around Lilah. Her mother has a knack for making Celeste feel that she’s bound to do or say the wrong thing – or already has.

The family shopping trip was something of a disappointment for Lilah, if not an outright failure. Celeste, as was noticed, never really got into the spirit of it. Astra was excited and chatty once they got to the mall, but Celeste was quiet and bored. She kept her mother and sister waiting outside the changing room for so long that Astra nearly fainted with hunger and Lilah began to worry that the absence of Sorrel has actually made Celeste more selfish than she’d been, which wasn’t what she’d expected. To top it all off, Celeste, who usually listens to her mother’s advice, bought not just one item that Lilah had advised her against but four, paying for the extra three herself. “I’m sure you know best,” Lilah told her with a smile, making it clear that Celeste didn’t.

Lilah, however, is a professional saleswoman; faint heart never clinched an important sale. And so, rather than discourage her, those small acts of rebellion have made Celeste’s mother even more determined to break what she considers the unhealthy hold Sorrel Groober had over Celeste – and, apparently, continues to have. Her attempts to separate them when Sorrel was alive didn’t succeed, but she has no intention of being defeated by someone who is dead. Time to let go. And so Lilah has encouraged Celeste to get out more. Using a gentle combination of bribery and guilt, she persuaded Celeste to accompany her to one party, two barbecues, a church fair, a brunch and the Skidmore and Pulaski Real Estate Boat Ride – events where she knew there would be other teenagers (though nothing came of any of them). Not nagging, of course, but suggesting (often and a lot), she convinced Celeste to invite Orlando and Ruben over to watch a film (Ruben couldn’t make it and Orlando fell asleep). Today Lilah is using a different technique.

Celeste is singing softly to herself when the door to her bedroom opens and her mother steps in, smiling. Like most of us, Lilah Redwing has a smile for every occasion. This is her selling-a-house-that’s-been-on-the-market-for-two-years-and-has-mould-in-the-basement smile. The technique she’s using today is deceit. “What are you doing, darling?”

This is another reason why Celeste doesn’t always want to be around her mother. What does she think she’s doing? Celeste is tempted to say, Sitting on my bed, playing my guitar. “Just messing around,” says Celeste.

Lilah’s smile intensifies. Besides the mould in the basement, there are raccoons in the attic. “Shouldn’t you be getting ready, darling?”

“Ready?” echoes Celeste. “I’m sorry, are we going somewhere?”

Her mother laughs. “Don’t tell me you’ve forgotten. Really, you girls…” She shakes her head. The things mothers have to put up with. “I know I told you. Iris Moon is coming to lunch.”

Celeste frowns. “Iris Moon?” She should have known there was some reason Lilah is home on a Sunday; it’s usually her day to see her friends if there aren’t any houses to be shown.

“Yes, Iris Moon.” Lilah’s laugh is like a picture over that damp patch on the wall. “You must remember. She’s quite an important figure in the community. I just sold her mother’s house over on Old Mill Road?”

Celeste rests the guitar across her lap, trying to coax this memory out of the corner where it seems to be hiding. The name Iris Moon is familiar, possibly because she’s such an important figure in the community – but not because Celeste knew she was coming for lunch. “You did?”

“Yes, I did. Remember? ‘It’s still Summer,’ I said. ‘It’ll be winter soon enough so we should take advantage of this beautiful weather to eat out on the patio more.’” She pauses for a second. “And socialize.”

Socialize. That sounds ominous. Iris Moon, Iris Moon, thinks Celeste. What is she not remembering about Iris Moon? “I guess I thought you meant you were having lunch with her,” lies Celeste. “Not me, too.”

“Nonsense. I was very clear. It’s an occasion. Astra’s invited Winnie. And Iris Moon is bringing her sister who’s visiting from DC with her son. And I bought all that lovely food at Barbieri’s.”

“You did?” Her mother never buys lovely food at Barbieri’s. You could buy a sheep for what they charge for a pound of shrimp salad. Maybe two sheep.

“Yes, I did. I told you, it’s an occasion. Iris Moon’s sister is in the government. It’s not every day we have someone to lunch who knows the President.”

“Or even every other day,” says a voice unheard by Lilah.

Celeste catches her breath, and moves her eyes to the left. Sorrel is sitting on her desk in lotus pose. She is not dressed to meet someone who knows the President; she’s dressed to meet someone who repairs automobiles. With effort, Celeste manages not to smile.

“Besides, darling,” says Lilah. Coaxing. “You know it was never meant to be just me and Iris. I am doing this for you.”

Celeste focuses on her mother again. “What?”

“For you,” Lilah repeats. “I’ve arranged this all for you. I’m sure I told you.”

Sorrel groans. “What do you want to bet this is about the nephew? You’re lucky it’s not legal to sell daughters, or you’d’ve been gone long ago.”

And that’s when Celeste remembers what she has been told about Iris Moon – or at least one of her relatives. Iris Moon’s nephew is in college, pre-law, and doing extraordinarily well. He has political ambitions.

“So the nephew’s coming to lunch, too,” says Celeste. Which explains all the lovely food from Barbieri’s – and why Celeste was never told about it.

“Well, of course he’s coming, too. They can’t very well leave him home by himself, can they?” Lilah’s smile becomes serious. “And you can’t spend the whole Summer sitting in your room playing your guitar, Celeste. How many times do I have to tell you? You need to get out and meet people.” Especially boys with promising futures. “Have a life. There’s nothing to stop you now.” Meaning Sorrel. “You’re not going to be young for ever, you know.”

“Oh for God’s sake, if she didn’t get palpitations every time you say you want to join a band you’d have a life and be meeting people all the time.” Sorrel slides gracefully from the desk. “And anyway you are still in your teens. You probably have a few good years left. If you don’t get hit by a car.”

“Celeste?” says Lilah. “Celeste, are you listening to me? Are you going to put on a dress?”

“Ooh,” squeals Sorrel. “Does she want you to wear the bright colours or the stripes?”

Celeste smiles. “You mean one of my new outfits?”

“I was thinking of something a little more conservative,” says Lilah. “After all, these are people who dine with senators and lobbyists.”

Celeste can feel herself getting ready to give in; she usually does. It’s always easier to do what her mother wants than go against her. Especially when you’ve been ambushed like this and have had no time to prepare your defence.

“Tell her to stuff it,” says Sorrel. “She’s always trying to fix you up with somebody’s nephew or son or grandson. What is she, your pimp? I swear, she’s almost as bad as my mother. And anyway, it’s Sunday afternoon, Cel. You’re going to yoga. Like we always did.”

Yoga. Celeste had totally forgotten about yoga. She and Sorrel would spend Saturday night at one or the other’s house, mooch around in their pyjamas all Sunday morning, and then go together to the yoga class in the room above the hardware store. Sorrel loved yoga; Celeste likes it okay, but mainly she went because Sorrel did. She hasn’t been back since Sorrel died; it never occurred to her to go without her. Celeste is the only member of the class who isn’t slim and who is only slightly more flexible than steel. That didn’t matter when her black mat was stretched out next to Sorrel’s green one. She could do anything, go anywhere when she was with Sorrel; Sorrel was like a free pass to life – accepted everywhere and welcomed with open arms. Sorrel showed her how to make an advantage out of being herself. Sorrel said she wasn’t odd, she was different – original, exceptional, unique. Celeste on her own is self-conscious and unsure. And very tall for a girl.

“Celeste? What’s wrong with you?” demands her mother, her smile hardening. “Are you going to get dressed? They’ll be here soon.”

But of course, Celeste isn’t on her own any more. Sorrel is keeping an eye on her. Sorrel is giving her a way to get out of this stupid lunch.

“I can’t. I’m sorry.” Celeste puts her guitar aside and stands up. “It’s Sunday, Mom. I have my yoga class. I have to go.”

“Surely you can miss one class.” If Lilah were ever home on Sundays she would know how true that is. “As a favour. To me. I told everyone you’d be here.”

“I’m really sorry, Mom. I have to go. I already paid.” Neither of those statements is actually true. “And, besides, it’s important to keep up.”

Lilah sighs, but it’s a sigh of compromise. “Just make sure you’re back in time for dessert.”

When the door shuts behind her mother, Celeste finally turns to face Sorrel. There’s no one there.

But she can hear Sorrel laugh. Job done.