Synopsis: Murder Lock: School of the Killing

Koutarou Kudou had the reputation of being the "Streets' Strongest." One day, his younger sister Hinami was kidnapped by a group of 13 thugs seeking revenge. Koutarou defeated all of them, but was subsequently arrested on suspicion of murder when each of the thugs was found dead that same night. He was then coerced into enrolling in a particular school that had a unique requirement for all its students to meet before being accepted.