"...a massive sinkhole opens in the middle of Los Angeles at the site of the 'La Brea Tar Pits' and Wilshire Boulevard. Hundreds of people, vehicles and buildings are pulled into its depths. The survivors find themselves trapped in a mysterious and dangerous primeval land where they must band together to survive.
"Investigators realize the sinkholes provide a temporary portal to the same location in 10,000 B.C. Meanwhile, the survivors struggle to find a way back through the portal before it closes up.
"Season Two revealed the sinkholes were caused by the 'Lazarus Project' run by people from 2076 who are working to find a way to deal with their time period's depleted resources as well as researching how to master 'de-extinction'..."
Click the images to enlarge...