The Taurus Reach: a remote interstellar expanse that holds a very old and potentially cataclysmic secret, the truth of which is feared by the Tholians, coveted by the Klingons, and dubiously guarded by the Federation. At the center of this intrigue is Vanguard, a Federation starbase populated by an eclectic mix of Starfleet officers and civilians, whose lives are forever altered as they explore the layers of mystery surrounding the Reach and steadily peel them away...one after another.

In the aftermath of Harbinger, Commodore Diego Reyes commands Vanguard while waging an intensely personal struggle, tasked to uncover the true significance of the Taurus Reach while simultaneously concealing that mission from his fellow officers -- and even his closest friends. As the Daedalus-class U.S.S. Lovell brings some of Starfleet's keenest technical minds to help, the U.S.S. Endeavour makes a find that could shed further light on the enigmatic meta-genome that has captured the Federation's interest -- if its crew survives the discovery....

Deep within the Taurus Reach, an ancient and powerful alien mind has awakened prematurely from aeons of hibernation, alerted to the upstart civilizations now daring to encroach upon the worlds in her care. With the stakes for all sides escalating rapidly, the alien lashes out with deadly force against the interlopers, propelling the Vanguard crew on a desperate race to understand the nature of the attacker, and to prevent the Taurus Reach from becoming a war zone.