The manga starts off pretty mild whit drunken rape (a common staple of Yaoi manga), but after that it starts becoming more soft and wholesome, whit the manga seeming to be one of those "I will help you get over your crush and show you love" manga whit "Seme Boss x Uke Soburinate" archetypes, basically a romance formed by a person trying to help the other open up and experience live, whit them going on a date, Kouichirou being boyfriend like and even seeming erritated whenever Shinobu would think about his best-friend that was his crush, (apart from the many dubious consent scenes), that is, until Kouichirou (seme) reveals his true self.
This is wen the manga becomes complicated, as while usually most cheating mangas don't really fool the reader, this one does that perfectly, since in the previous chapters it made it seems like Kouichirou was truly trying to make Shinobu (Uke) love him (more on this later), leaving a much bigger feeling of betrayal and unlike-ness towards Kouichirou, while also making the readers extremely protective of Shinobu.
This all starts whit having Kouichirou distancing himself from Shinobu all the sudden, whit their only interacting being a sex scene on the office after Shinobu forces them to have communication, but after that scene, back to the same, leading Shinobu to go search for Kouichirou in him home, only to spot him taking some guy he met at the bar home.
Once Shinobu confronts him in the next chapter right on the start of Vol.2, he says that he is simply a subordinate and takes the random guy up to his room and ends up having sex whit him after braking Shinobu heart and his trust.
And so we start Vol.2, where for the first chapters we end up whit the perspective of Kouichirou soon after Shinobu leaves the main branch, right after having sex whit Kouichirou for the last time and thanking him for showing him how he doesn't need to hide his face behind glasses anymore and finally being able to attend his best-friend wedding.
We first learn that all this time Kouichirou was only planning on making Shinobu fall for him just as a game, to eventually drop him of the side of the road like an a-hole, as he did.
But eventually Kouichirou starts to realize that none of the guys he was sleeping whit gave him the same feelings as Shinobu did, how the memory's of the time they spent, their date, his expressions, the way he felt, how just hearing his name would make him depressed once he was gone, and ends up realizing that he was in love whit Shinobu all this time, realizing that his whole "game" was less of a game then he thought it was.
The realization of how much of an ass-hole he is and how he hurt the first love of his life starts consuming his life, he becomes extremely depressed, starts drinking heavily, dozing off mind work, and ultimately starts to seek Shinobu out once Shinobu travels to the main branch to deliver some work, only to end whit Kouichirou running to the train station desperately and not reaching in time.
We are then introduced to a split perspective of both characters, we are introduced to Shinobu new workspace, where he seems much lively-er and is now his workplace "idol", but we soon learn that Shinobu saw Kouichirou searching for him wen sitting on the train to depart, and starts wondering wath Kouichirou wants whit someone he has played whit.
Depressed Kouichirou keeps going on and eventually Shinobu has to go to the main branch once more, Kouichirou asks to have a private conversation whit Shinobu and reluctantly Shinobu is forced to do so because of the Boss - Employee status.
Kouichirou apologizes to Shinobu and confesses to him and explains how he has been so engrossed in him since he has left, only to be shut down by a cold Shinobu claiming to not be tricked by sweet words, while also self-degrading himself because of how much the betrayal hurt him.
This leads Kouichirou into traveling to the sub-branch Shinobu is now working at and ambushing him wen he is leaving the company, claiming that Shinobu isn't any of the things Shinobu said he himself was, and telling him he is the best men he has ever met in his life, but Shinobu, despite obviously still not being over Kouichirou, tells him the best he can do for him is leave, and so Shinobu once again shuts Kouichirou down.
This encounter leaves Shinobu thinking about Kouichirou and the things he said, thinking that he didn't seem dishonest, but he brushes it off once he is told he has to attend a meeting in the main branch.
While having this meeting, the malnutrition and fatigue from the long ongoing depression over Shinobu finally hits Kouichirou, and so he colapses, being taken to the hospital in the process.
While there, Shinobu requests to stay whit Kouichirou and realizes that the colapse was do to Kouichirou being extremely depressed and letting himself go over their "breakup" and the guilt he was feeling for the actions he had done, and so Shinobu lets his feelings surface while also still being afraid that he cannot trust Kouichirou.
Once Kouichirou wakes up, Shinobu asks him to tell him his true feelings, and once Kouichirou does, Shinobu reciprocates but tells him that he is afraid to trust him again, whit a more softer Kouichirou claiming that he will do all he can to regain his trust from now on, which is a drastic change from Vol.1.
And so, the manga ends, whit a "before break-up extra" (I think) and a "post back togheter extra" showing the new Kouichirou who now acts much softer.