After a mishap at the Reincarnation Support Department, 17-year-old Riichi Hourai finds himself reborn as a succubus, a creature that thrives on draining men's life force through dreams. Unwilling to partake in such acts, Riichi discovers an unconventional source of sustenance in milk. However, in a world devoid of cows or milk-drinking races, the odds seem stacked against him. With the help of a dairy cow provided by the Rehabilitation Support Department, Riichi embarks on a risky journey to nurture his lifeline and suppress his succubus instincts. Little does he know, this cow harbors secrets beyond imagination. As Riichi strives for a tranquil existence, he unwittingly gets entangled in world-altering conflicts. Despite a past tragedy where Riichi and his best friend perished in an accident, only for the friend to be reincarnated later, their paths have yet to cross again. Will fate reunite these friends? Can their bond withstand the test of reincarnation and newfound powers? Join Riichi and his friend on a whimsical romantic comedy as they navigate their extraordinary new forms and rediscover their friendship.