This one’s for MechWarrior:

It’s December 2766. All of the PCs, for whatever reason and whatever their origins, are on Terra over the traditional holiday season. On the morning of the 27th, they’re all at a diplomatic function (or on duty, or waking up hung over…) in Unity City. That’s when the shooting starts… and they find themselves the only protagonists standing between Stefan Amaris’ coup and Helena Cameron.

This campaign would be heavy on action-espionage and outright military action as the PCs try to get a Cameron heir off world, out of the Sol system, and to something resembling safety. Depending on the mix of PCs, both character-scale and wargame-scale conflict could be feasible.