She stares at their reflections in the space helmet, brow wrinkling. “Is it true that if you were in a spacesuit and it got a hole in, your blood would boil and your lungs would explode?”

Santi considers her worried face and thinks about how to answer. “Depends,” he says. “If it was a small hole, the suit would decompress slowly. You’d just run out of air and fall asleep.” He gives her a reassuring smile. “Any other questions?”

“Yes, actually. I wanted to ask you about windows.”

“Windows?”

She nods enthusiastically.

Santi has no idea where this is going. At least he can expose her to the museum a second time while she finds her point. He leads her back through the hall of spacesuits toward the planetarium.

“So there’s a window in my attic that looks out into the garden,” she begins. “Or, it should look into the garden, because it’s on that side of the house. But it doesn’t. It looks into somewhere else.”

“Somewhere else?” He’s half-listening, half-concentrating on the exhibits scattered through the ground floor of the planetarium, trying to guess which one might spark her interest. He pauses in front of a display titled “PROXIMA B: EARTH’S CLOSEST EXOPLANET.” He wonders wryly if the word “closest” might put Thora off.

“Yes,” says Thora, ignoring him and walking on. “I know because it doesn’t have the bush that should be under that window, the one with the white flowers. Instead there’s this building, but it doesn’t look like a real building. More like—a dream of one.”

“That sounds very strange.” Santi slows down as they come out of the planetarium into a dead end. Ahead of them is a closed-off room hung with a yellow sign reading “im Bau/Under Construction.” Santi goes up to the barrier, trying to peer through, but the space beyond is dark.

“Excuse me,” someone says in English.

Santi turns. A tall man with long hair, wearing a bright blue coat. The apparel suggests museum staff, some kind of educational entertainer for the children, but the expression doesn’t match: he looks anxious, like there is something he needs to say but he doesn’t know how. The way Héloïse used to look, before she left.

“I’m afraid that room isn’t ready yet,” the man says. “However, we do have another room you might like to see.” He points to the right, where Santi remembers a wall papered with an image from the Kepler telescope. Now, a door hangs open.

The man looks back and forth between them with a nervous smile. He probably thinks Thora is Santi’s daughter. His stomach twists, thinking of the children he and Héloïse never had. He smiles. “Sure, we’ll check it out.”