Something a bit specific:
MC: My Character
YC: Your Character
MC is a college student who is very socially awkward. He is generally looked on as weird and a loner. Most people think that one little thing will make him snap and do something crazy. He is very much to himself and quiet, unable to express himself most of the time.
YC is a party boy who drinks and loves to hang out with lots of people at a time. He could be considered a frat bro, but doesn't necessarily belong to one. He is very much so MC's opposite in a lot of ways.
MC met YC when YC got tutoring in Math class. MC and YC have been best friends pretty much ever since, after YC got over MC's initial weirdness. YC feels like he knows MC very well, probably better then anyone else, even his family. YC and MC have spent a massive amount of time together over the past year, and YC's other friends are worried about him. Indeed, YC and MC are inseparable. YC drags MC to parties and MC sulks in the corner.
MC has been in love with YC pretty much since they met and has no idea how to express it. YC is very much so known as a lady's man, having been with several women over the past year. However he feels towards MC something far more then he's ever felt for any women he's been with.
After about a year, MC does something absolutely horrible, by accident. Something sociopathic. It could be a murder or a rape. It could be a hit and run that leads to someone's death. It could be any number of things as long as it's massive and extreme and accidental. YC tries to wrestle with this and wants to protect MC, despite what happened. This is especially true if YC is the victim or sole witness.
That is the basic outline. Details will come in discussions. If interested PM me.