The year is 2552. Humanity is locked in a struggle for survival against the Covenant, a collective race of aliens that have declared humanity's existence as an affront to their gods. The planet Reach, a major naval shipyard, has fallen to the Covenant. Forced to make a blind jump into Slipspace during the battle, The Pillar of Autumn carries onboard what may well be the last Spartan-II, Spartan-117, known only by his rank, Master Chief. But he is not the only Spartan onboard. Sealed in six cryo tubes are the only Spartan-IIBs ever created. The crew assumes that they're the results of the Spartan-II enhancement project that was occuring on Reach at the time the planet fell.

They're wrong.

There's a number of odd things about the Spartan-IIBs. For one thing, they're all female. For another, they seem to posess abilities no human has ever had. And there's a reason... but it's one not even the Spartan-IIBs know about - or expect.

As The Pillar of Autumn emerges from Slipspace in unknown territory, the Covenant closes in...

Note: This is a Halo crossover, with an altered continuity. I'll be drawing heavily from the first Halo, and from the book The Flood.