There's no lock Detective Dobin Kim can't open. With his unique "opening" ability, he can unlock anything—even people—to get the information he needs to hunt down criminals and solve crimes. Enter Locker—his polar opposite and his enemy. When Locker uses her ability to "lock" a witness and prevents Kim from accessing key information in a crucial case, they plunge into a cat-and-mouse game with justice itself at stake. When two equal forces collide, who will emerge the victor?