After barely escaping an explosion at Mason Industries, Wyatt (Matt Lanter) and Rufus (Malcolm Barrett) chase the Mothership back to a French battlefront during World War 1 to rescue Lucy (Abigail Spencer) from Rittenhouse. There, they discover that Lucy has recruited Marie Curie, the famous French scientist and the only person ever to win two Nobel Prizes, to help save the life of a wounded American soldier, only to learn that the soldier is Lucy's own great-grandfather who Rittenhouse is bringing to the present to be their leader.
The Time Team chases Rittenhouse to a stock car race in the 1950s where Wyatt learns that his favorite race car driver is actually a Rittenhouse sleeper agent on a mission to destroy the American car industry. To stop the Rittenhouse plan, Wyatt, Lucy and Rufus team up with Wendell Scott, the first African-American NASCAR driver.
When a Rittenhouse sleeper agent in 1941 Hollywood steals the only copy of Citizen Kane, Lucy, Wyatt and Rufus team up with Hedy Lamarr to get it back. Hedy Lamarr turns out to be not only a glamorous movie star but also a scientific wizard whose discoveries led to the invention of Wi-Fi.
When Rufus and Jiya add a fourth seat to the Lifeboat, for the first time ever, Connor Mason joins the team as they travel back to the dusty backroads and smoky juke joints of the Depression-era South to rescue the life and legacy of Robert Johnson, who, legend has it, bought his musical genius from the devil for the price of his soul. Meanwhile, Agent Christopher keeps Wyatt in the present to execute a dangerous raid on Rittenhouse headquarters.
The Time Team travels back to 1981 Washington D.C. on the day President Reagan was shot, only to discover that the Sleeper's target isn't the President, but a young rookie police officer, none other than Agent Christopher.
With a little help from their future selves, Lucy and Wyatt, along with the rest of the team, journey to the California Gold Rush and the Korean War's Hungnam evacuation in a daring bid to save Rufus and stop Rittenhouse once and for all.