"Welcome back. I've been waiting for you." Okada Yu, a new nursery school teacher, is on a field trip to Sanrio Puroland with his students. As they're about to head home after a fun day, his vision suddenly distorted... They wander into the mysterious amusement park Uropia where they're confronted by a strange yet oddly cute creature called "Froggy Egg". To escape from Uropia, he and the children must challenge the park's attractions and collect 10 medals... Will the 16 children and their nursery school teachers be able to escape safely? Or...?