Miyuki, a woman invested in her career, has a secret. That secret is that she used to be the leader of a local gang group. She kept that fact swept away, but Hiroyuki Yamashita, the most dull guy from work, some how figures it out...! "I'll keep your secret away with you" he says that, and stirs me from the inside, almost as if he's a different man!? His stamina and strength is way more powerful than expected... Everything feels so good...! Yamashita, who are you!?