Wen, a seven-year-old girl, is on vacation with her dads, Eric and Andrew, at a remote lakeside cabin in New Hampshire. Their cabin is isolated, with no neighbors nearby.

One day, while playing outside and catching grasshoppers, Wen sees a stranger walk into the driveway. His name is Leonard. He’s huge, the biggest person Wen has ever seen, but he seems kind and friendly, and they quickly become comfortable with each other.

Suddenly, Leonard becomes serious. He apologizes and says, “None of what’s going to happen is your fault.” Soon, three more people arrive, holding strange, scary-looking objects.

Wen runs to warn her parents. As she does, Leonard calls out: “Your dads won’t want to let us in, Wen. But they have to. We need your help to save the world.”