After a quarrel with her father Sachi took her sword and went on a quest. She was captured by a man who placed a red collar on her throat and sent her to the coliseum, where 8 contestants battled for the same prize: freedom. Anyone who loses becomes a sex…

Yuina woke up in an unfamiliar forest… She wondered aimlessly inside to meet a succubus who has lost her body and memories. They join forces to reach their goals: Yuina, to go back home, and the succubus, to get her body back. Their journey begins now.