Nijigasaki High School is located in Odaiba, Tokyo. The school is popular due to its free school style and diverse majors. The story centers on the members of school idol club in Nijigasaki, and their attempt to prevent the club from being abolished.
The anime follows a salaryman who has a chance meeting with a girl named Ai on the train. They begin to meet every Monday on the train, with the man serving as her bodyguard on the crowded commute while they chat.
16-year-old Hayate is really down on his luck. Because his unemployed parents are good-for-nothings who waste what money they have on gambling, Hayate had to start working at a young age to help out his family. Although such experience has made him inhumanly fast and tough and skilled at things boys aren't normally skilled at, it has also left him in an awkward position, as his parents have racked up such a huge gambling debt that they have sold Hayate to the yakuza for the value of his organs. In a desperate attempt to avoid that fate, Hayate decides to become a "bad guy" and kidnap someone to be held for ransom, but his efforts to do so are mistaken as a confession of love by the girl he targets. When he helps save the (as it turns out) ultra-wealthy 13-year-old Nagi from real kidnappers, she takes him in and gives him a job as her new personal butler (and love interest) until he can pay off his debt. But Hayate is more attracted to Nagi's beautiful teenage maid Maria, and head butler Klaus is initially disapproving of a boy with such a poor look. And then there's Nagi's pet Tama, who is also a force to be reckoned with.
Miyamo Chio, a first-year at the completely ordinary high school Samejima Academy. Chio just wants to get through her school life without standing out too much, but for some reason, all kinds of obstacles await her along the path she takes to school. Her long-time friend Nonomura Manana, who's trying to quit being an otaku; the flawless Hosokawa Yuki, who occupies the top caste in the school; and lots of nameless people about town find themselves in Chio's path as she employs the (useless) techniques she's acquired from her Western video games in her daily efforts to get to school.
Ko Ichinomiya's family motto is "Never be indebted to anyone," but after losing his pants and falling into the Arakawa River, he quickly finds himself in debt to his savior, the cutely insane Nino who happens to live under the bridge. To repay her, he vows to help her with her desire to "experience love." Along the way he'll meet the river's other residents, including a hot-blooded kappa, a Sister in drag, and a literal rock star.
This is Gameindustri. Beings called Goddesses rule the countries of this unreal world. The four goddesses govern four states: Planeptune, Lastation, Lowee and Leanbox. For many long years these countries fought each other over the Share, the source of the Goddesses' power. However, fearful that the conflict would pointlessly erode their strength, the goddesses signed a Friendship Treaty forbidding them from taking the Share by force. Under the treaty, the Goddesses and their younger sisters took a step forward to a new stage in their relations. It is the dawn of a new, dynamic era marked occasionally by shared laughter, disputes as well as cooperation. But what does the future hold in store for Gameindustri...?