Ever since he was a child, zombie-obsessed Chihiro Furuya has wanted an undead girlfriend. Soon enough, his love for all things zombie comes in handy when his cat Baabu gets run over, prompting Chihiro to try to make a resurrection potion and bring him back to life. During his endeavor, he sees a rich girl named Rea Sanka yelling into an old well every day about her oppressive life. After meeting and bonding with her, Chihiro is convinced by Rea to persevere in saving Baabu. Eventually, he succeeds with the help of the poisonous hydrangea flowers from Rea's family garden. Unaware of the potion's success and seeking to escape the burdens of her life, Rea drinks the resurrection potion, mistakenly thinking she will die. Though it doesn't kill her, the effects still linger and her death from a fatal accident causes her to be reborn as a zombie. With help from Chihiro, Rea strives to adjust to her new—albeit undead—life. For a boy wanting a zombie girlfriend, this situation would seem like a dream come true. But in Sankarea, Chihiro's life becomes stranger than usual as he deals with Rea's odd new cravings and the unforeseen consequences of her transformation. [Written by MAL Rewrite]

Hashiba Sora has fallen from a 4th story window and has lost all of his memories. When Fujimori Sunao comes to his school as his new room mate, Fujimori tells Hashiba that he is called Ran. Fujimori and Hashiba both have a split personality which they developed in their youth. Their split personalities, Yoru and Ran, are deeply in love. Even though it creeps Fujimori and Hashiba out what their other selves do with each other at night, they also start to fall for each other. Because of their relationship, Hashiba Sora finds out a lot of shocking facts about their youth.

A long time ago, Zeus, the great god, created a three–tier hierarchy of angels, top, middle and lower, although they were supposed to be equal. Also, Zeus appointed 6 angels as Saint Beasts who govern the animals of Earth. They were: Go, the seiyu; Shin, the genbu; Rei, the suzaku; Guy, the byakko; Yuda, the kirin; and Ruka, the hooh. However, Kira, the shooting star, and Maya, the fuga, didn’t attend the selection tests and left for the Earth. The six angels fulfilled their tasks faithfully. However, because of Zeus’s increasingly tyrannical acts, they begin to mistrust him. (Source: AnimeNfo)

The seal which was imprisoning the fallen angels, Kirin no Yuda and Houou no Ruka, is broken and the two decide to get revenge on the God who had cast them to Hell by getting rid of the Heavens that had once been their home. Soon the guardian angels on Earth begin disappearing, and no one in Heaven can explain the happenings. But there is a sense of a vengeful animal spirit at work, and so the four Saint Beasts are called upon to investigate. The 4 Gods of Beasts attempt to rescue the guardian angels, as well as to find out what this evil animal spirit is... (Source: Wikipedia)