On the surface, MK ENT. appears to be an ordinary event management company, but in reality, it is a front for contract killings. Among its assassins is Gil Bok-soon, a legendary killer with a flawless 100% success rate—yet also a single mother raising her teenage daughter, Jae-young.
Though unrivaled as the ace of her industry, Bok-soon struggles with the clumsy, fragile bond she shares with her daughter. Determined to break down the wall between them, she contemplates resigning. While stalling her answer to CEO Cha Min-kyu’s offer of a contract renewal, Bok-soon takes on what she intends to be her final assignment.
But when she uncovers a hidden truth behind the mission, she defies the company’s unbreakable rule: once sanctioned, the job must be carried out at all costs. Her defiance sets off a deadly chain of consequences, making her the prime target not only of MK ENT. but of every killer in the business.
Now, Bok-soon faces an inescapable showdown—kill or be killed.