Orange Planet is about a girl named Rui, a high school student in love. One day, while delivering a love letter, Rui finds herself caught in a fire! Eisuke, the owner of the apartment that caught fire, says that since he saved Rui from the fire, that he should live in her home! This will be a problem for Rui, because her childhood friend, Tarou, lives next door and often comes into Rui's house unexpexctedly. Will Rui be able to put up with Eisuke living in her home without being caught?