Nadeshiko, a high school student who had moved from Shizuoka to Yamanashi, decides to see the famous, 1000 yen-bill-featured Mount Fuji. Even though she manages to bike all the way to Motosu, she's forced to turn back because of worsening weather. Unable to set her eyes on her goal, she faints partway to her destination. When she wakes up, it's night, in a place she's never been before, with no way of knowing how to get home. Nadeshiko is saved when she encounters Rin, a girl who is out camping by herself. This outdoorsy girls story begins with this first encounter between Nadeshiko and Rin.

Yume Nijino aims to become a top idol, and she enrolls in the Yotsuboshi Gakuen (Four Stars Academy). This academy has a special group called the S4, who are the top four active idols in the school. Yume and the other first-year students aim to become a part of the S4.

Haru Chitose, Eri Kumagai, Sarasa Ryuuouh, Kiri Mukae, Uori Mukae, Sasame Mitsukuri, Miku Nishio, Hiyo Yukino, Shupe Gushiken, Kotoko Kintoki, and Roro Morooka are the eleven members of "Music Girls," an idol group produced by Pine Records. However, they're a third-rate idol group that can't seem to sell CDs at all. But even though they're obscure and constantly in debt, the members and their producer, Ikehashi, are all trying their hardest. Ikehashi gets the idea that Music Girls needs a new member—an idol who can light a fire under them so that they can grasp success!

A fifth-year elementary student named Eiji Toomatsu, and his "inspiration" buddy, a dog named Pochirou. One day Eiji finds a mysterious book called the "Pikachin Research Book," and learns about the seven tools that make up the Pikachin Kit. Eiji presses a button inside the research book, and immediately a "Future Amazon" delivery arrives at his door with the kit. Eiji uses the blueprints included in the box to assemble the kit, but it seems as though 1% part of the kit is still missing. In the franchise, the word "Pikachin" means the flash of inspiration or insight one gets about a new project, similar to the visual of a lightbulb turning on above one's head when someone has an idea. The concept of the franchise is "invention is 99% plastic models, 1% inspiration."