The story takes place after the TV drama series Ossan's Love (2018). It's been a year since Haruta and Maki pledged their undying love. Haruta has now come back and receives a warm welcome from familiar faces, his boss Musashi Kurosawa and other colleagues. Justice Yamada, a recruit who has been recently assigned to this branch, welcomes him too. One day, completely out of the blue, the headquarter-based project team "Genius 7" shows up at the Second Sales Branch. Project leader Jin Mamiana orders the Sales team to support them in their big project. Maki, who had been transferred and works now at the head office, is among the project team members with Mamiana. Haruta and Maki grow apart, and Haruta teams up with Justice. Then Kurosawa gets involved in an accident and loses his memory, but the loss of his memory is selective and he has forgotten only Haruta. However, when Kurosawa sees Haruta, he falls in love again.. Hilarious and heartwarming, the final battle of Ossan's Love begins.

在某房地产公司供职的业务员春田创一（田中圭 饰）是一个相貌平平的大男孩，他喜欢巨乳美女，日常经常被上司训斥，被后辈挖坑，事业无成，恋爱无能。偶然的机会，他发现部长黑泽武藏（吉田钢太郎 饰）居然偷拍了许多关于他的照片，而且还经常给他写一些暖心却暧昧的鼓励话语。不久，武藏当面向创一表白，并承诺要为了他离婚。五雷轰顶的创一不知所措，殊不知更大的混乱还等在后面。从总公司调来的后辈牧凌太（林遣都 饰）亲切和蔼，他在住进创一的公寓后不久，竟也向创一示爱。不久后，两个基友更为了争夺创一吵翻了天。
对于创一来说，这可真是可怕至极的桃花期……