From Fantasyshrine:
High School Senior, Yokozeki Haruhito has always been watching the teacher-in training, Arisawa Yuya. However, this doesn't go unnoticed by Yuya's cousin, Yuma. Yuma volunteered to be Yuya's substitute. Things started to escalate when one day Yuya walked in on them while they were kissing…
Two families are tied together by a curse. Every 100 years, one person from each family must share the same fate for exactly one year. The pair will be subjected to twelve misfortunes, where one will get hurt while the other must sustain their injuries in return.
When Kagura Izumi was seven, his parents died in an accident. Since then, he has been living an ordinary life. Until the day of his seventeenth birthday, when he meets a mysterious transfer student, Ichijyou Chihaya. However, this fateful encounter between them is only the start of their intertwined fate. For the next year, the two of them will be forced to face 12 misfortunes on the 13th of every month, a curse that has never left any previous pair alive.
Although only 19 years old, using his good looks and his body as a weapon, Kanzaki Nao is a natural gigolo. After being stabbed as a result of a bad breakup, he is saved by a refined and dangerous man who is a Yakuza: Murou Ryouichi, head of the Ichinose Group. Murou stops Nao from leaving the city after his wounds have healed and brings him to his apartment, offering him a deal in order to pay for Nao's treatment.
Even though Murou tells him that he's "not interested in brats", his words are contradicted when he starts kissing Nao like a lover. What will happen to Nao who swears that he definitely won't fall in love…..?