I point the binoculars back at the moon. “See those big shadowy areas? When people were first looking at them, they thought they were bodies of water, so now we call them ‘lunar maria,’ which means ‘seas of the moon.’ They gave them all kinds of weird and interesting names.”

I lower my binoculars again. “Like what?”

He starts listing them off. “Lake of Sorrow, Lake of Happiness, Sea of Serenity, Marsh of Decay. We also have Bay of Roughness, Bay of Rainbows, Lake of Dreams, Lake of Fear, Sea of Waves. Then there’s my personal favorite: the Sea that Has Become Known.”

Once again, I’m semi-stunned by all the knowledge floating around in that head. “How do you remember all of that?”

He smiles, and his body relaxes into the chair. “I’ve been studying for a long time. My mom and I used to do it together. She worked one summer at this resort in Maine. It had incredible views, and her boyfriend had a telescope he’d let me use.” He trails off, and then I’m thinking of all the entries about his mom. I want to ask about her, but that feels way too private. I already know too much.

“So Simon, Emma, Nova, and the other girls. Are they your…” I’m trying to ask how he’s connected to them, but I’m not sure how to do that without being nosy. Tell me all your personal family details, stranger.

His cheek tightens slightly, then he glances out at the sky. “I’m, ah…” He takes a deep breath, hesitating, before meeting my eyes resolutely, like he’s made a decision. “I’m in foster care. Simon and Emma are my foster parents.”

His words hit me hard. His voice is light, but there’s a falseness to it that makes me think he’s hiding pain, and suddenly I remember all the parts of his star log where he talked about new cities, new homes, more moves. Regret spreads heavily through my chest. I shouldn’t have brought it up. I don’t know what being in foster care means exactly, but I can only imagine that it must be tough. My problems shrink down until they’re microscopic in the moonlight.

“I’m sorry,” I say. “Is your mom….”

“Not here,” he says quickly. “But it’s only temporary.”

I’m hunting for any words to match this enormous thing he’s told me when Mason suddenly stiffens. He points toward the garden, and when I lean over, I see a flash of movement. It’s a person. The figure moves into the light, and when I see the hair color, my heart drop faster than a shooting star. “Mason, my mom!” I whisper.

Mason’s reflexes are like a cat’s. He drops even faster than I do, and the two of us lie flat.