Superior

I love this concept!!

So essentially, a superhero's intern/apprentice meets a villain's intern/apprentice and they fall for each other. Jamie (the superhero's intern) knows his job inside and out. He knows he's going to be kidnapped and used as a pawn to draw the attention of Captain Superior, but he's okay with that. During one of his almost regularly scheduled kidnappings at the hands of Terrorantula, he meets Tad, the villanous intern, and he's hot. It's forbidden, but they can't help themselves.
Over the story, Jamie has to consider whether Tad is actually evil or not. He has to deal with the decisions Tad makes and the consequences of them, and decide whether persuing something with him is something he can actually do.

I loved Superior, and I kind of wish it wasn't just a novella.
It's surprisingly sweet, but maybe I'm just a sucker for a M/M romance where they're on opposite sides.