Mara Carlyle's senior year is going as normally as could be expected, until - wa-bam! - fellow senior Katelyn Ogden explodes during third period precalc. Katelyn is the first, but she won't be the last teenager to blow up without warning or explanation. As the seniors continue to pop like balloons and the national eye turns to Mara's suburban New Jersey hometown, the FBI rolls in, and the search for a reason is on.
Keri Cleary is worried about her brother, Alistair. Everyone is worried about Alistair. As the one witness to a shooting, he has been shocked into silence. But everyone needs to know three things: Who shot Kyle Dwyer? Where is Charlie Dwyer? What does this all have to do with the disappearance of Fiona Loomis? Perhaps the answers lie in stories. As Alistair makes strange confessions to his sister, Keri becomes inspired.
Alistair Cleary is the kid who everyone trusts. Fiona Loomis is "not" the typical girl next door. Alistair hasn't really thought of her since they were little kids until she shows up at his doorstep with a proposition: she wants him to write her biography. What begins as an odd vanity project gradually turns into a frightening glimpse into the mind of a potentially troubled girl. Fiona says that in her basement, there's a portal that leads to a magical world where a creature called the Riverman is stealing the souls of children.
Twelve-year-old Alistair Cleary has washed up on shore. But where? It seems to be Aquavania, the magical realm where children create entire worlds from their imaginations. There's something wrong, though. The creators have disappeared, and the worlds are falling apart.