Prologue: Wammy's

A new girl comes to Wammy's. And soon befriends Matt and Mello. Pranking ensue and everything is fine. Until Mello leaves. What will happen to Matt? How far will she go to protect them both? And will she be able to change their fate?
Slight MattxOC Warning spoilers in later chapters

So the first half of this is just crazy rubbish that I think up, but it gets more serious when Mello leaves. So if you wanna read the crazy rubbish do so. But if you don't I suggest that you skip to chapter 20 xD