A story type of game. The set would come with a 300 point team of unique figures to use, plus a few army squad characters and a "boss" type bad guy for the gamemaster to play as. There would also be a few terrain pieces that go with the story and a book with all the scenerios.
every round there's a new map to build and some story that the gamemaster reads. The hero player gets his figures the set comes with plus whatever other unique hero's the current map says to use (like agent Carr could join the party for a map). Then the gamemaster is told to use whatever army figures from the expansion set plus 200 points (or whatever) from the master set. And of course each map would have different special conditions.
The boss figure would be a character the heros fight twice (once in the middle of the campain and again at the last map). instead of the "basic" game stats on one side of his card he has a lower point version of his character. So the heros don't fight the real version till the last map.
The players get points for remaining figures they have left(maybe even play different maps wether they win or lose certain battles), and the points they have at the end of the campain determines the ending they get. Overall, they'rd be about six maps with optional rules on some of them to play with more than two if you want to play them by themselfs afterwards.