Ever since he was young, Chihiro Furuya has been fascinated with zombies and yearned for an undead partner. His peculiar passion proves useful when his cat Baabu meets a tragic fate, driving Chihiro to concoct a resurrection potion. Along his quest, he encounters Rea Sanka, a girl from a wealthy background, venting her frustrations by an old well daily. Through their growing connection, Rea inspires Chihiro to persist in reviving Baabu. With the aid of toxic hydrangea blooms from Rea's family estate, Chihiro achieves his goal. However, when Rea, unaware of the potion's potency, consumes it to escape her troubles, a surprising turn of events unfolds. Instead of perishing, she undergoes an unexpected transformation, becoming a zombie after a fatal accident. With Chihiro's support, Rea navigates her peculiar new existence as an undead being. While Chihiro's dream of a zombie girlfriend seemingly materializes, life takes a bizarre turn in Sankarea as he grapples with Rea's unusual cravings and the unanticipated repercussions of her change.