About what you might expect from an NTR/drugs/corruption doujinshiYou know... this would've been a real different story if she'd offered herself up like that to pretty much anyone else... a lot darker.
I mean, he was drunk at the time, and from the looks of it, that was the last time they had seen each other until she got hired in the company. Take into account when she met him (a 2nd or 3rd year high school student) and how many years it takes to graduate a university in Japan, you're looking at 5-6 years of separation. I don't blame the MC for forgetting after not seeing her for that long, especially since it didn't look like she gave him her name that night. She only knew his from the business card, which she had held onto since then as we have seen in a previous chapter.Bro is fuckin' dense that didn't even realize that the highschool girl he met years ago is now her kouhai, oof