Star Trek: Vanguard #2: Summon the Thunder

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.