Piece of Cake

Piece of Cake is a Japanese manga series written and illustrated by George Asakura. It was serialized in Shodensha's josei manga magazine Feel Young from July 2003 to December 2008, with its chapters collected in five wideban volumes. A spin-off manga, titled Piece of Cake: Bangai-hen, was serialized in the same magazine from March to June 2015. A live action film adaptation directed by Tomorowo Taguchi premiered in September 2015.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.

Poster © the film's rights holders.