In "Sankarea: Undying Love," Chihiro Furuya has an unusual fascination with the dead, especially female zombies. After his beloved cat Baabu dies accidentally, his obsession grows, and he begins experimenting with a potion meant to bring the dead back to life. Despite repeated failures, Chihiro nearly gives up on his goal to resurrect Baabu.
Just before he abandons the effort, Chihiro meets Rea Sanka, a beautiful but deeply troubled girl, who inspires him to keep trying. By adding toxic hydrangea petals to his potion, Chihiro finally creates the elixir he has been seeking. Unbeknownst to him, Rea drinks the concoction, believing its poison will end her life. After a fatal accident, Rea dies, but the elixir works, bringing her back as a zombie.
Freed from her oppressive past, Rea chooses to live with Chihiro, who now must use his knowledge of the undead to care for the teenage zombie girl.