The Arithmetic of Echoes by Senan Mahon

Echoes can get you into trouble, when you don't know who's listening.

The Velmarn, a cold creature of unimaginable power and reach, basks in the silence of the multiverse. Watching, waiting for the reverberations that will awaken its wrath. Its long-vanquished enemies have hidden for millennia, wary of its return. Now, with humanity's discovery of the cosmos-spanning M-drive, the reclusive aliens must reveal themselves to warn us of its folly.

XRD agent Danpah ends his exile to be their messenger, but his warning reveals an unsettling mystery. The custodians of the classified M-drive have not been using it. Someone else has been making unauthorised leaps with the technology, unaware of the risk it poses. Someone with the resources to steal its hard-won secrets and make good use of them. Someone who bears a grudge of genocidal proportions and a brutal determination to right the wrongs of the past.

In the midst of this chaos, a family desperately searches the galaxy for a missing daughter and her lover, in a quest that seems destined to fail. The young couple's reckless abandon has placed them in grave peril, at the heart of the M-drive mystery. With only their quick wits to rely on, they must tread lightly but act decisively, if there is to be any hope of survival.

A grand-scale hard science fiction epic combining multiverse mechanics, deep-space espionage, and the chilling arithmetic that comes from making echoes in the dark forest.

(430 pages approx.)