From publisher blurb:
Following the trail of the ancient trekth leads the adventurers to another planet, one already ravaged by the progenitors—Seretse. Once there however, leaving proves to be a difficult task and there is great need for the intervention of powerful outsiders. Elemental armies besiege the asteroid fortress of the prevailing warlord Garajax the Vicious and within his alien chest beats the key to the conflict barring the party's way to learning more about what threatens their world.
What's inside Heart of War:
An adventure on a different world for PCs of 22nd level.
Statistics for elite alien shock troops, the alien warlord, and armies of elementals (earth and fire).
The Heart of Primordial Flame, a potent artifact that offers whoever takes it great power—but not without cost.
More details about the mysterious Trekth and the effects of their world runes.
Pregenerated adventurers of 22nd level for every class.