When Siamwit School falls on hard times, the school administrator Paphada decides to merge Udon Phithak campus with the main campus, Thep Burapha. The two campuses have long been at odds with each other, and now they'll be sharing one roof for the next school year.

Saint, the head of class M.5/2, doesn't care about school or anyone in it. In middle school, he headed a gang of bullies. Now, he's met with rebellious, temperamental and stubborn Shin. In the past, Saint and Shin were close friends, but something happened between them that put a violent end to their friendship. The friction between the two causes a classroom war and teachers Jan and Sung have to put their differences aside and come together to put an end to the fighting which will require a reconciliation between Saint and Shin.