The Edge of the Sword is the first of three novels in the Errand of Vengeance novel series.
Lt. Jon Anderson is the newest security officer aboard the U.S.S Enterprise. He joins the crew at a time of mounting tension between the Federation and the Klingon Empire. Previous battles have been inconclusive, but Starfleet Command fears that the Klingons are gearing up for a major offensive. The Enterprise would be on the front lines of an all-out interstellar war.
But Lieutenant Anderson has a secret: he is actually a Klingon infiltrator assigned to sabotage Starfleet from within. His first mission: kill Capt. James T. Kirk.