I invited her to dinner half-jokingly, but she surprisingly said OK!? I never thought that Tsubaki Sannomiya, who is plain, quiet, and hard to approach, would actually accept my invitation... I have a girlfriend too, so I thought I would have dinner at a family restaurant and wrap it up casually and go home, but I was surprised to be invited to "drink again at my place after this"... I got on board with the invitation thinking that if I could get laid once, it would be fine, and we had sex at her house. And the next day, surprisingly, Tsubaki-san thought that she was dating me...