In the world of Akamaru Jump, a group known as Sket Dan is formed to aid those in need. Despite the lack of clients, the trio - Bossun, Himeko, and Switch - often laze about. Their routine is disrupted by a new client, Mimori Konno, who seeks their help to deliver an envelope with a heart symbol to her crush, Naoki Nishio. Initially hesitant, Bossun urges Mimori to take the task herself. However, upon discovering risqué photos inside the envelope, the Sket Dan shifts gears, intrigued by the mystery, and embarks on a mission to uncover the truth.