Kaname Okiura, a student of Prefectoral Umineko Shougyou High ("Umishou" for short), joined the school's swimming club in order to learn how to swim, but the club is filled with weirdos, let alone who can teach him swimming. Then, a sunny, happy-go-lucky girl named Amuro Ninagawa who transferred from Okinawa joined the club. Her extraordinary underwater speed and unorthodox swimming style (plus her personal habit of nude swimming—a powerful magnet to teenage boys) surprised every club member, especially Okiura, because she reminds him of a mermaid-like creature he saw only once in his early childhood.

Fifteen-year-old Chacha is a typical teen with an atypical talent: she can communicate with cats. Though her friend Mito thinks this is the coolest ability in the world, Chacha finds her unique skill to be annoying at best and disruptive at worst. Whether she's dealing with countless strays proposing marriage, neighborhood cats offering to help her with tests or waking up to 'presents' on her bed in the night, Chacha's normal school life will be anything but!

Pet shop owner's daughter Chika Tokorozawa spends every waking hour with her dog, Rin Tin Tin, who repays her love by watching over her while she sleeps. Based on the manga in Young Sunday magazine by Maki Otsubo, who is better known in the manga world for Mr. Cinema.

When aliens known as the Oni threaten to invade the Earth, they promise to leave under one condition—a randomly-chosen human must win a one-on-one game of tag against Lum, the beautiful daughter of the Oni leader. The "lucky" person selected happens to be the lustful and unlucky high schooler Ataru Moroboshi. Given 10 days to attempt to grab Lum's horns, Ataru realizes how impossible the challenge is as he is faced with Lum's extraterrestrial powers. Motivated by a promise of marriage from his childhood friend Shinobu Miyake, Ataru manages to catch Lum off guard. He mistakenly grabs hold of her bikini top first, but he eventually achieves his true goal. Although the game is over, Lum misunderstands that she is the one whom Ataru wants to marry, and she decides to move in with him. The poor student constantly tries to shake off the clingy Lum while doing his best to reconcile with his desired fiancée. After Ataru's heroic feat results in such a disastrous outcome, it is questionable whether luck will ever be on his side.