You're mine and I'm yours

Ezra has been in love with his best friend, Sophia since they first met in third grade. Now a middle schooler, he wants to confess his feelings to Sohpia, but unfortunetely gets friendzoned before he can even utter a word.
Heartbroken he has to deal with the rejection and continues to stay by Sophias side, as a "friend".
One day Ezra meets Sophia's brother, Mathias, who's a high schooler. Even though everyone talks about Mathias like he's a big and tough guy, he turns out to be quiet annoying. But what is the reason for his annoyence?