An official spin-off delving into Ushijima's past! An official spin-off from the popular dark hero manga "Ushijima the Loan Shark" is here! The story is set in a juvenile detention center. The protagonist is a young Ushijima Kaoru. Before he even encountered the world of loan sharks, in the winter of his second year of junior high school, Ushijima swung a metal bat at Wanido Sanzo's head after a fight with the Wanido brothers, and was sentenced to juvenile detention for assault. What will Ushijima think on his first time in juvenile detention? At the same time, key characters like his classmate Karasaki, Shishitani (his older brother), who runs the loan shark company "Shishik" where Ushijima later works, and Nageki, the leader of the Monshudaa Rengo biker gang, are also living youthful, sharp, and brutal lives. This ensemble drama depicts the younger Ushijima and his friends' lives untold in the main story.