Eun Seonmyeong is a hunter and exorcist who carries two curses on his body. He takes on a commission to kill a target—the Fire Fox Sim Iyul. Instead of killing him, Seonmyeong ends up forming an alliance with the Fox and begins an uneasy cohabitation. The two live together, managing to get along mostly well despite their mutual dislike and suspicion... until Iyul's Heat Cycle arrives. Driven purely by instinct, they spend a passionate night together. After that night, they realize they are no longer just allies or reluctant roommates—they are something slightly different...