Daidabashi Kenzo is your usual student living on his own...
His only real concern is that he can't get "it" up....
Carrying the weight of his burdens, one day Kenzo discovers a girl, asleep, and clinging to his ceiling!
The girl, called Kugeyama Sakura, explains that she's a ninja, sent to protect a seal placed on Kenzo's body.

[From DLsite English]