Star Trek: The Motion Picture - Echoes #3

Akris, a maniacal doppelganger of Chekov from a parallel universe has begun working with the Romulans on a superweapon with a promise to reduce the Federation and its allies to ash. But with half the bridge crew in Romulan custody, it´s up to Spock and McCoy to hold down the ship and devise a plan to get their captain and crewmates out of enemy hands!