Cloak and Dagger, the stellar Laws of Magic fanfiction début of our very own CuddlyTogas, is now on fanfiction.net, at the other end of this link.
Now, I'm getting a little partisan here... but it is utterly superb. There is simply no reason for not reading it (and the rest of the LoM fic on the Internet too, naturally - but this is a heck of a place to start from if you haven't already).
Here's a summary, as per Togas herself (which does the thing no justice, but is better than anything I could do):
"Rational? What's rational about magic? Trumped-up, self-important poseurs making things happen that have no right to happen. Dangerous stuff." - Captain Tallis, Word of Honour, page 235
Aspiring magician Pompey Craddock attends university and meets an eternally-suspicious young man called Tallis. This is the story of how they met, how they fell in love, and how they - eventually - worked things out.