We Who Are About To Die Salute You

The player's Adepts are up against a force so staggeringly great they have no real chance of facing it and surviving.  That's not to say they can't win, they just can't fight and live through it.  Maybe they're soldiers holding off an invading army long enough for their own nation's forces to mobilize and arrive, or maybe they just have to buy someone enough time to pull something off.
Whatever the larger story, the fact remains that this scenario is about a group of Adepts who know this will be their final battle.  With nothing left to lose, they throw everything they've got into a no holds barred throwdown with evil.