Karen Inuyama is an office worker who loves fine muscles. Her blissful moment is interrupted by her nagging coworker, Takuma Hosokawa.

Today was our regular house-drinking party. The place was Hosokawa's house.

A series of happenings lead her to discover an unexpected side of Hosokawa-kun.

I can't believe he was hiding something like that!

The battle against the cynical coworker is about to begin!
「その筋肉、触らせてください!!」　細マッチョな同期と専属マッサージ契約!?　男子の筋肉が大好きなOL、犬山かれん。ある日会社の同期、細川くんの秘密を知ってしまう…彼は隠れた“細マッチョ”男子だった!?　細川くんの身体に、筋肉に触りたい！　かれんは専属マッサージ契約を結ぶことに！　見て・触って・恋をして？　筋肉LOVE・コメディ、スタート！