This story begins after all of the Arcobalenos already break their curses. So Adult!Arcobaleno. And also Nurarihyon No Mago -Not the Sennen Makyo-
Sawada Nana, the mother of Sawada Tsunayoshi is actually the supposed-to-be-dead daughter of Nurarihyon, or the 1st heir of Nura Clan. So, Tsunayoshi Nana's son have half of human's blood, quarter of Vongola's blood, and another quarter of Nurarihyon's blood.
After the fight, Sawada Tsunayoshi and his guardians are having a peace life or it's supposed to be.. Everyone except Tsuna are having a peace life. At night, Tsuna always felt his blood boil and that ruining his time to sleep. Good thing Reborn is on his vacation though.
Tsuna, every night, every each night felt his body is on fire and his blood boil. He also felt unease. There is some weird aura around the town which make Tsuna's blood boil and felt unease. But at morning Tsuna felt like always. Go to school like always.
I don't own KHR and Nurarihyon No Mago at all!