Stardate 49548.7   When the U.S.S. Voyager enters plasma cloud, while being pursued by Vidiian vessels, a series of astounding consequences occur. Before the ship is able to clear the cloud, the engines stall, anti-matter supplies begin to drain, and Proton bursts causing significant casualties and a hull breach. Without warning, Ensign Kim and Kes disappear into a mysterious void in space and Captain Janeway discovers a duplicate U.S.S. Voyager and crew in a parallel universe.
While the U.S.S. Voyager crew contends with the most significant disaster to befall on the vessel, Captain Janeway discovers that a divergence field has caused all sensor readings to double and every particle on the ship to duplicate but there is still not enough anti-matter to sustain both vessels. When the Vidiians begin to close in, the two Janeways meet to determine a solution, knowing that only one of the two ships can survive.