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...
Wait, was that microwave also Excalibur...
...أيمكن أنّ ذاك المايكرويف كان إكسكاليبر
Entonces, ese microondas era Excalibur...
Espere, esse micro-ondas 
também era a Excalibur...