Percy is trying to finish his first year of college in peace. He hasn't angered any gods or fought any monsters in months. He thinks his near death days are behind him until suddenly he is transported to a strange city. Kara Danvers is on a rampage to save everyone she can get her hands on, because if she doesn't stop then she doesn't have to think about how much she misses Mon-El. Everything changes when a lost boy meets a woman who is just trying to help. Percy and Supergirl must team up to battle enemies from both of their pasts and figure out how to get Percy home and who is responsible for sending him to National City.