Deja Vu. On Mardi Gras in New Orleans, the ferry Sen. Alvin T. Stumpf is carrying hundreds of sailors and their families across the Mississippi River from their base to the city.
Suddenly, the ferry explodes and sinks, killing 543 passengers and crew members.
Special Agent Douglas Carlin from the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) is sent to investigate and discovers evidence of a bomb planted by a domestic terrorist.
Arriving at the scene he meets with local investigators and FBI Special Agent Paul Pryzwarra, and informs them of his findings.
He learns about and is invited to examine a partially burned body pulled from the river, identified as Claire Kuchever, which was reported to the authorities minutes before the explosion.
Pryzwarra is impressed with Doug’s detective expertise, and asks him to join a newly formed governmental detective unit whose first case is to investigate the bombing.
Led by Dr. Alexander Denny (Adam Goldberg), they investigate the events before the explosion by using a program called “Snow White”.
It enables them to look into the past (4 days, 6 hours, 3 minutes, 45 seconds, 14.5 nanoseconds) in detail by (according to Pryzwarra) using several satellites to form a triangulated image of events.
The system is limited in that they can only see past events once; there is no fast forwarding or rewinding, although they can record everything in the process.
Convinced that Claire is a vital link, Doug persuades them to focus on her.
While the team observes Claire’s past through “Snow White”, the bomber calls her to talk about the SUV that she advertised for sale.
He doesn’t buy her car, but the “Snow White” team now knows exactly where and when he was during the call.
Doug finds out “Snow White” is actually a time window, and can send inanimate objects into the past.