In present-day Tokyo, a grieving father named Yuichi Kimura seeks revenge after an unknown assailant killed his son and then told him he wanted to meet at a bullet train station. Meanwhile, ex-assassin “Ladybug”, after coming out of therapy, is assigned to pick up a briefcase from the same train station. Ladybug is hesitant at first, as her last few missions have resulted in a series of accidental deaths. Also on the train in question is a woman with the code name “Prince”, as well as two assassins carrying the briefcase that Ladybug must take. Of course, the situation quickly degenerates and things get crazy.