In the aftermath of the Dropsite Massacre at Isstvan V, a battered and
bloodied force of Iron Hands, Raven Guard and Salamanders regroups on a
seemingly insignificant death world. Fending off attacks from all manner
of monstrous creatures, the fractious allies find hope in the form of
human refugees fleeing from the growing war, and cast adrift upon the
tides of the warp. But even as the Space Marines carve out a sanctuary
for them in the jungles of Pythos, a darkness gathers that threatens to
consume them all.