リコ（与田祐希）たち三姉妹は、ふと家中が謎のアイドルグッズで溢れていることに気が付く…。その謎のアイドルの正体とは、母がハマっている推しだった！アイドルに侵食されまいと小向家の危機を脱するため、早速リコたち三姉妹が調査を開始すると、想像以上に沼へとハマっていることが明らかに。
いい“推し変”がないかと考えたリコは、母を連れて矢島模型店へと向かう。母娘でプラモデル作りをすることで、徐々に母の胸の内を知ることに…
Riko (Yoda Yuki) and her three sisters suddenly notice that their house is filled with mysterious idol goods... The true identity of the mysterious idol is their mother's favorite idol! In order to escape the crisis of the Komukai family not being consumed by the idol, Riko and the other three sisters immediately begin their investigation, but it becomes clear that they are more addicted than they imagined. Thinking about whether there is a good "change of favorite idol", Riko takes her mother to Yajima Model Shop. As mother and daughter build plastic models, she gradually learns what is in her mother's heart...
