Not much is notable about the lecherous Ataru Moroboshi, but his extraordinary bad luck sticks out like the horns in an alien's head. When Earth is threatened by a fleet of alien invaders known as the Oni, Ataru is selected to represent humanity in a duel against one of them. It's a stroke of rare luck for Ataru that the duel is in fact a game of tag, and that his opponent is Lum, daughter of the Oni's leader, who places her personal dignity above victory—as Ataru finds out by seizing Lum's bikini top and with it, victory. However, misfortune kicks in again when Lum mistakes Ataru's promise to marry his girlfriend, Shinobu Miyake, as the desire to wed Lum herself, and decides she rather likes the idea. Wielding her influence as an alien princess, she moves in with him. Forced to deal with the consequences of his womanizing ways, Ataru must balance his crumbling relationship with Shinobu while keeping Lum happy, all the while flirting with every woman he meets.

After their loss against Suzuridani Academy, the members of the Keishin Academy girls' basketball team—Tomoka Minato, Maho Misawa, Airi Kashii, Hinata Hakamada, and Saki Nagatsuka, along with their coach, Subaru Hasegawa—exert more of their time and effort in improving in the sport day by day. However, this time around, new rivals with strengths possibly exceedings theirs and friends appear on their way to the top.

For as long as Akari can remember, she and Hiroyuki have always been friends. But with time, everything changes, and her feelings have turned into something more. As a new semester of high school begins, will the two childhood friends come closer together or drift further apart? Join Hiroyuki, Akari and all their friends—the bubbly Shiho, the quiet Serika, the lovely Kotone, and more—in this heartwarming tale of love, relationships and friendship!

Six short "Special Broadcasts" (omake) were produced and aired after selected episodes. They lasted around five minutes and followed the general style of the main anime, although the characters are drawn as chibis.