Typical rom-com manga in which a teen boy, Taira Daichi, is reunited with a forgotten childhood friend, Hoshifuri Sosogu. Years ago, the pair promised each other to marry when they grew up, but Daichi's forgotten. Now his parents are away for a while and he gets to live with Sosogu, a budding pop idol.
Essentially an elaborate fake-out by creator Okawa Bkub, first as a prelude to the renewed publication of his 4-panel manga Pop Team Epic, then done as a running gag for announcements for the strip. The series resurfaced during Pop Team Epic's anime as an April Fool's joke announcement, and was subsquently used as the namespace for the show website and Twitter account. Each PTE episode also ends with a "next time" preview of a nonexistent GirlDrop episode.
In February of 2018, the series got an actual, non-hoax official anthology comic. For brevity's sake, the anthology will be going here.