The mysterious Baek family moves to Kumsu city and opens the "Pawfect Haven Animal Hospital." The same day a young woman, Lee Yu-jin, is reported missing in Kumsu mountains. Worries of a serial killer called "Doom-veloper" surface. The Baek family son, Ji-hoon, and daughter, Ji-woo, are threatened by local bully Jo Kyu-tae. They decide to take their problem home to Mother, Han Young-su, to remedy.