Gin-san takes history lessons, and teaches you how to hide your porn mags?
Tsukuyo tries to teach Seita history, the subject he's not great at. However, her training (?) methods end up leaving him scarred, which makes desperate Seita ask Gin-san to take over as his tutor...
that would eventually tear 
the two heroes apart.
مما أدّى إلى فراق البطلين المُحتم
que terminaría por separarlos.
que acabou separando os nossos heróis.