Uta Koi tells the "super-liberal interpretation" of the Hyakuninisshu anthology compiled during Japan's Heian period of 100 romantic poems from 100 different poets such as The Tale of Genji's Murasaki Shikibu.

Far from the city's noise lies Torishirojima—a quaint and peaceful island where time seems to move slowly. Hairi Takahara, a young boy nursing a wounded heart, uses the recent death of his grandmother as a quiet reason to leave the city for a summer retreat to Torishirojima. Upon reaching the island, Hairi finds himself surrounded by a refreshing, laid-back atmosphere, a far cry from the hustle and bustle he is used to. After moving in with his aunt, Kyouko Misaki, he prepares to spend the summer helping her sort through a shed full of artifacts his grandmother collected over the years alongside his cousin, Umi Katou, who is staying with them. While adjusting to the island's slower pace, Hairi decides to spend his free time exploring. He soon meets the cheerful Tsumugi Wenders; the antisocial Shiroha Naruse; the wandering Kamome Kushima; and the sharp-tongued Ao Sorakado. Drawn into their lives and the island's subtle mysteries, Hairi is gradually swept up in a summer filled with fun, nostalgia, and life-changing moments that will stay with him forever.

Wataru Minakami is a top student who failed his high school entrance exam because of a computer glitch. He later discovered that he was accepted to Stargazer Hill Academy, which is located at a mysterious place called Promised Island. At the request of his father, Wataru is whisked away to the island, and before he can settle in, a dozen of cute and charming girls start to flock him and claim to be his younger sisters. As Wataru gets closer to his newfound siblings, a deeper mystery as to why they were sent to the island comes to play. (Source: ANN)

Chinami Ebihara is girl with a strange ability to generate electromagnetic waves when her emotions run high. However, since this "ability" affects anything electrical, it resulted in her having to transfer from school to school when she was younger. As Chinami, now 18 years of age, transfers to a new school, she once again affects the electronic devices in the school, but this time, when another student, Kotaro Kannagi, sees her do this, he becomes obsessed in studying her "TYPE-E" ability.