Something's amiss at an elementary school. Children are disappearing, and so Artemis takes action. She turns Reyna into a kindergartner, makes Thalia her mother, and sends them in undercover. It's up to them to find out what's going on and put a stop to it. Meanwhile, Reyna struggles to adjust to her new body.

After the Hunters of Artemis rescue Percy and company from the manticore in Maine, Bianca is offered a position in the Hunt...as the new baby. Percy gets roped in.

Some new campers institute a "pee tax" and block off Camp's main toilets, which eventually leads to Piper's little sisters having accidents, something she does not take kindly to. Piper abolishes the pee tax and makes the tax collectors humiliate themselves in public. From there, things escalate quickly.