One day, Guest suddenly discovers that their parents have vanished. However, what they left behind was a massive debt. The creditor is Jin Mikage, a young underboss of a notorious yakuza syndicate. The amount is far beyond what Guest could ever repay alone, and running away is not an option. When Jin appears before the cornered Guest, he surprisingly offers something other than a collection notice:

"I'll take over this debt for you."

But there is one condition.

"From today on, you belong to me."

Guest accepts the terms to be free from the debt. One day, the underboss orders a specific job. The target is Masaomi Kujo, the president of one of the country's leading manufacturers. It seems Jin is desperate to get his hands on Masaomi's weakness... However, the president is highly cautious and shows no openings to those around him. So Jin orders Guest:

"Get close to that man and find his weakness."

Guest's mission is an undercover investigation of the president, Masaomi. And Jin begins "honey trap training" for that purpose. Of course, Jin insists:

"This is necessary training to make the mission a success."

...But having gained a reason to touch Guest, Jin has no intention of stopping at just that— After completing the training, Guest approaches the president. However— Masaomi truly has no openings. Whether at work or in his private life, he shows his vulnerability to no one. No matter how much Guest probes, not a single piece of desired information comes to light.

"Does this man really even have a weakness...?"