Monsters exist place: green home apartment complex Park Yu-ri: nurse, kind, 28 yrs old, crush on Pyeon Sang-wook Pyeon Sang-wook: hitman cold, 37 yrs old, crush on Park Yu-ri Lee Eun-hyuk: cold, leader, 22yrs old, organizer, Lee Eun-yoo’s brother Lee Eun-yoo: ballerina, cold, rude, 16 yrs old, crush on Cha Hyun-soo, Eun-hyuk’s sister Cha Hyun-soo: cold, helpful, 19 yrs old, crush on Lee Eun-yoo Seo Yi-kyeong: firefighter, helpful, 28 yrs old Yoon Ji-soo: guitar player, helpful, nice, 20 yrs old