The Daichis are a family in danger of tearing itself apart. Dissatisfied and money obsessed mom Seiko has served wimpy and otaku dad Mamoru with divorce papers. Daughter Nozomi who has always been saddled with all the housework, feels pained that everyone is using her. The youngest albeit most foul mouthed, Dai is forced to watch all this as everything is going to pieces. However when the Galaxy Federation recruits the Daichis to combat alien threats to the wellbeing of the Earth, it will be a chance for the family to save the world and maybe themselves.

There have been many cases of stolen songs happening among the idols in Yokohama District recently. Even super idol Marine Amagi's hit song "Kiseki no Uta" was taken away. At the request of Marine, the Milky Holmes team starts investigating the case.

Summer break has arrived, but while his other classmates are out having fun, Kimihiro Watanuki continues to work as compensation for the eccentric Yuuko in her shop. With the spirits and supernatural phenomena that bother him lessening, he pays his dues by cleaning, cooking, and doing whatever else the apparently lazy Yuuko needs. Watanuki, however, gets involved in a new predicament when Yuuko receives a mysterious invitation to a mansion whose owner seeks Yuuko's wish-granting ability. When he, Yuuko, and his classmate Shizuka Doumeki make their way to the peculiar residence, they meet others who were summoned by the same strange invitation. All of them are collectors of various unique items, drawn there by the chance to expand their collections. But as the collectors begin to disappear one by one, Watanuki and his companions must solve the mystery and put the case to rest, or find themselves in risk of danger.

The protagonists of the series are the three Kisugi sisters—Hitomi, Rui and Ai—who run a café called Cat's Eye. The sisters lead a double life as a trio of highly skilled art thieves, leaving cards with the name "Cat's Eye" at the scene of their crimes. They steal works of art that belonged to their long-missing father, Heinz who was a famous art collector during the Nazi regime, in the hopes of him contacting them. Toshio, the police officer investigating this case is the fiancé of Hitomi. He also swears to capture and bring down the Cat's Eye Gang.