In the present, Benjamin Schröder, a history professor in South Carolina, has a mental breakdown dealing with the sudden appearance of a second set of memories as real and compelling as what he thought of as his normal life. Then, as he nears recovery, Raibert Kaminski appears at his door. He claims to be a historian from the thirty-first century with a story of how sixteen alternate histories have been bound together in a Knot—which Schröder holds the key to unraveling. If Schröder can’t help, each of those universes will come to an explosive end. But the cost to Schröder is less abstract and incredibly monstrous, and soon the two are facing a ruthless threat that shows no respect for the denizens of the past. The usual Tom Clancy-esque exposition of technical details that readers expect from Weber are leavened by absurd humor and bloody action. Echoes of Robert Heinlein mix with the inventiveness of Charles Stross and lots of exploding temporal spaceships and bodies. Weber and Holo must have had a ball writing this action-packed temporal/multiverse-travel novel.
Can confirm; David and Jacob had an ABSOLUTE ball. 😁
*Review is behind paywall.