I'd go with "Operation: Duo" or something. and have that the name of mission there on.
But, names are the last thing you should worry about really. I'm taking a screenwriting class right now, in college. and the instructor never looks at the title, I called one assignment "Class Assignment 1" as the title. Just give it a Working Title for now, and as you develop it a name will hit you...thats how it always works for me. I start writing it, and once the story is fully developed i always imagine the opening sequence and title first, to seet up what mood im going for.