Rin is an ordinary student who has, up to now, devoted his time to studying instead of to romance and friends. This situation shifts only when he encounters the lovely Ena, who appears to inhabit a completely different world. Rumors suggest she maintains several boyfriends simultaneously and has slept with more than 100 men, but she is not particularly bright, which is why Rin agrees to tutor her. Soon, his lessons prove successful, and as thanks for raising her grades, Ena devises something special for the nerd...