Way Down We Go

What happens when the prank was all planed by Snape in order to break up the Maraurders? He tries to frame Sirius and Regulus but causes them all to become friends instead. Now Sirius, Regulus, and Peter have to prove Snape did this to them. (As well as get revenge.) This changes the outcome of every character and the entire war.

(I suck at summeries.)