Ever since starting high school, Kyou Nukui has skipped every single class. Instead, he spends his days confined to his bedroom, composing music and uploading it online alongside illustrations by his sole friend, an artist known by the pseudonym "Kiriyume." One day, Kyou tentatively uploads his latest composition, TR03, which marks his first deviation from his usual style. Furthermore, he does not post under his standard handle "HibikiP," but rather under the simple name "me," and without an illustration from his enigmatic friend. Not long after, Kyou receives a very polite email that not only praises his music but also somehow identifies him as the composer behind TR03. The email requests a meeting at a nearby park, and he cautiously agrees to attend. To his surprise, however, he discovers three elementary school girls at the rendezvous point! Suddenly, Jun Gotou, Nozomi Momijidani, and Sora Kaneshiro ask for his assistance in holding a concert at their home, an old church that now serves as an orphanage. Although Kyou is initially hesitant, he eventually agrees to their proposal after witnessing their musical talents. Based on the light novel of the same name by award-winning author Sagu Aoyama, Tenshi no 3P! follows Kyou as these three angels transform his life.