Members from the Enterprise are on a routine away mission when they witness a fiery crash. They pull a single survivor from the wreckage-a young woman who looks eerily familiar. Her presence begs questions that hit close to home. And the answers will send shockwaves throughout the future as they know it.

Will, Data, and Deanna beam down to Nervala IV to retrieve an instrument left behind the last time Will discovered his transporter double,Thomas there. They only have a two hour window to accomplish their task and get out until another window opens up in 8 years. But when the time to return to the ship comes, only 2 officers make it to the beam-out spot on time...