After losing his mother, 14-year-old Taro journeys to Tokyo to live with his grandfather. But he gets the biggest surprise when he discovers that his grandfather's home is a huge mansion with hundreds of beautiful maids ready to serve him. Making matters worse (at least for Taro, but not for our viewing) is that not only does he inherit the Hanaukyo mansion, he gets the services of all of the maids 24 hours a day, 7 days a week.

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.

Mini-OVA specials bundled with each Blu-ray/DVD volume of Kenzen Robo Daimidaler.

The protagonist Wu Liuqi originally lived a carefree life on Xiaoji Island, but his identity became a mystery due to amnesia. As outsiders landed on the island and recognized Wu Liuqi, various conspiracies began to cover Xiaoji Island. So Wu Liuqi decided to return to Xuanwu Kingdom to meet his destiny in order to protect his partners and their homeland.