To write his research thesis, a man conceals his identity and steps into the gang, a world completely unlike his own. There, he encounters various young men, each with tattoos that symbolize both their rank and the sins they bear. Yet, as he spends more time with these gang members, his emotions start to shift in unexpected and subtle ways— **Original Manhua:** [Renta!](https://tw.myrenta.com/item/308581?ac=a-t41c5), [Bomtoon](https://www.bomtoon.tw/detail/qingtui), [BookWalker](https://www.bookwalker.com.tw/serial/27095)