“But you paid for it, right?” Tabitha says.

“Right,” Harper says with a wink. “With my hard work and exemplary attitude.”

Tabitha can’t bring herself to care that Harper stole a bottle of champagne from her workplace. What does it matter?

“We won’t get a chance to drink it anyway,” Tabitha says. “I’m nursing.”

“So pump and dump,” Harper says. “I’m sure you have enough breast milk stored in the freezer to feed the Gosselin kids. This bottle has our names on it.”

“Whatever, Harper,” Tabitha says. She feels teary again for no reason; maybe because she desperately wants to drink champagne, but she just can’t. Julian starts to cry, and Harper says, “There’s my baby.” She points at Tabitha. “You sit. Or, better still, go take a nap. I’ll handle the kids, then get started on dinner. You look like Flat Stanley.”

Tabitha wants to protest. She wants to remind Harper that she has no idea how to take care of a toddler or a sick infant; it’s not something she can bluff her way through. But Tabitha is too tired to state her objections. The idea of a nap, an uninterrupted nap, followed by a home-cooked meal is too seductive to turn down.

As it turns out, Harper is a competent nursemaid and an excellent cook. She makes a bouillabaisse filled with scallops, mussels, and chunks of lobster. Tabitha eats three bowls with salad and crusty bread to sop up the juices, and then, amazingly, she feels like a human again.

Harper’s arrival on Nantucket is, in fact, an answer of sorts. Ainsley is two years old and newly verbal; she asks questions nonstop, the most frequent of which is Why? To which Harper chooses among three answers:

Because there is pie in the sky.

Because there’s a sty in my eye.

Because the guy makes me sigh.

Ainsley accepts all three responses with a solemn nod, as though she is being handed valuable pieces of wisdom.

Harper is also terrific with Julian. She doesn’t mention how pallid he looks; she doesn’t compare his feeble crying to the sound of a windup toy that is running out of windup. She treats him as though he were a normal baby. She calls him stud and stallion. And when he’s inconsolable and won’t settle or nurse, Harper dances him around the room, singing “If I Had $1000000,” by the Barenaked Ladies, which puts him instantly to sleep.

Wyatt is impressed. “She’s good with him.”

Tabitha nods. Half of her is resentful that Harper has proved so skillful with the children, but half of her is relieved. She has slept more since Harper has been here than she has in the three months prior.

On her last full day, Harper gets up early and rides Tabitha’s bike into town. She comes home with a bouquet of wildflowers that she bought from one of the farm trucks on Main Street.

“Something to remember me by,” she says, putting the flowers in water and leaving them on the kitchen counter. “And by the way, we’re going out tonight.”

“No, we’re not,” Tabitha says.

“Yes, we are,” Harper says. “Wyatt okayed it. He’ll stay home with the kids. He thinks it’s a good idea.”

“He does not think it’s a good idea,” Tabitha says. Wyatt is terrified of being left alone with the children, which is one reason for Tabitha’s exhaustion.

“Well, I talked him into it,” Harper says. “We are going to drink the champagne I brought, we are going out to dinner, and we are going to dance at the Chicken Box.”

At this, Tabitha laughs. There is no way they’re dancing at the Chicken Box. Tabitha hasn’t been to the Chicken Box since her first summer on Nantucket. “I don’t think you get it,” she says, “because you live a life free of responsibility. But I have two children, Harper. I’m a mother. I can’t just go out on a wild bender.”

“Who’s talking about a wild bender?” Harper says. “We’ll put the kids down, then go out. We have an eight thirty reservation at 21 Federal. Then to the Box for the first set. Home by midnight. It’s all arranged. You’re not allowed to back out. You need this, Tabitha. I’m afraid if you don’t let some steam off, I’ll be back here next month to commit you to Sapphire Farms.”

Only now that so much time has passed can Tabitha effectively analyze why she let Harper talk her into going out. Was it the mention of Sapphire Farms—the mental institution for genteel Boston ladies who suffer mental breakdowns? Eleanor had several friends who had gone to Sapphire Farms, ostensibly because they needed “a break from the city,” though the twins knew a trip to Sapphire Farms meant that these ladies were either batshit crazy or at least unable to cope with daily survival. Was it that Tabitha was afraid of Harper, unable to stand up for herself and say no? Was it that being set free from her life—even for a matter or four or five hours—was too tempting to resist?

Yes. Harper had presented an irresistible opportunity. She was the serpent offering an apple from the forbidden tree. And Tabitha, being a vulnerable and weak mortal, had taken a big, juicy bite.

Tabitha doesn’t remember being nervous or worried. She doesn’t remember asking Wyatt whether he was really okay with letting her go out; she doesn’t remember going back to give Ainsley and then Julian one more kiss. She does remember putting on a gauzy white sundress. She remembers letting Harper braid her hair. She remembers plucking a marguerite daisy from the bouquet of wildflowers and sticking it behind her ear.

They decide to carry the bottle of Billecart-Salmon down to the end of Old South Wharf, where Harper pops the cork off into the harbor and they sit on the edge of the dock with their feet skimming the surface of the water as they pass the bottle back and forth between them, swigging and swilling and delighting in the lawlessness of it.

Or at least Tabitha is delighting in it. She feels like a new person—or, rather, like an old person, the person she was before she became a mother at twenty-two.

They put on their sandals and walk to 21 Federal, Tabitha’s favorite restaurant. Tabitha thinks about calling to check in with Wyatt, but she doesn’t. If she hears the baby crying, her night will be ruined.

They are seated at a two-top in the front room of the restaurant. They split a starter of portobello mushroom over Parmesan pudding, then they split the pan-roasted halibut and a bottle of very cold Sancerre. They split a crème brûlée. Everyone in the restaurant is looking at them, doing double takes. Twins. Identicals. There are men at the bar who offer to buy them an after-dinner drink. The men are well-dressed, older. They look wealthy. They look married.

“Ignore them,” Harper says. “They’re just into the twin thing.”

But Tabitha doesn’t want to ignore them. She never imagined she would feel desirable again, and these men seem so self-assured, so worldly. This was the kind of man Eleanor meant her to marry, she is certain. Eleanor did not mean for her to spend her life with a housepainter who doesn’t even have halfway decent health insurance. Tabitha winks at the men, then flutters her fingers in a wave.

“No,” Harper says, pulling Tabitha up by the arm. “We are not going down that road tonight, Pony.”

Outside, Harper flags down a taxi, and they proceed to the Chicken Box. Harper buys them two beers apiece, then they wend and weave their way up to the front row, where they can see the band.

They dance with abandon, hands in the air. The band plays “With or Without You,” by U2, and Harper throws her arm around Tabitha’s neck and the two of them belt out the truest words ever written in a song. For them, at least.

I can’t live… with or without you.

They stumble home sometime after one in the morning. The hem of Tabitha’s dress has been trampled; the braid is falling out of her hair. But she is happy. For the first time in months, she is happy.

The house is quiet, and Tabitha shushes Harper, who is giggling and rummaging through the fridge for something to eat.

“Can I make popcorn?” Harper asks.

“Too loud,” Tabitha says.

She tiptoes into the baby’s room, and immediately her milk comes in. She groans at the prospect of pumping and dumping and heating up a bottle. She bends over to kiss her son. Because she is so drunk, so delirious with wine, music, and freedom, it takes her a moment to realize that something is wrong.