Captain Benjamin Sisko takes the Defiant back in time and into a parallel universe so that he and Data can undo the vile sabotage that triggered the Temporal Apocalypse. Meanwhile, Admiral William T. Riker's grasp of reality becomes more tenuous by the minute. Can Deanna Troi free him from madness before it is too late? Starfleet's heroes risk everything to set time right. But will Captain Jean-Luc Picard let Beverley Crusher and their son die? Or...

Two years after the USS Voyager's return from the Delta Quadrant, Seven of Nine finds herself rejected for a position in Starfleet and instead finds a new home with the interstellar rogue law enforcement corps known as the Fenris Rangers. The Rangers seem like an ideal fit for Seven, but to embrace this new destiny, she must leave behind all she's ever known, and risk losing the most important thing in her life: her friendship with Admiral Kathryn...