Terra Nova follows an ordinary family on an incredible journey back in time to prehistoric Earth as a small part of a daring experiment to save the human race. In the year 2149, the world is dying. The planet is overdeveloped and overcrowded, with the majority of plant and animal life extinct. The future of mankind is in jeopardy, and its only hope for survival is in the distant past. In the two-hour Season Finale, the 11th Pilgrimage arrives in Terra Nova and the mysterious Phoenix Group in 2149 makes its move to pillage the past with the help of Lucas and Mira. Meanwhile, Jim and Taylor team up in a last stand against the Phoenix Group, a colonist makes the ultimate sacrifice and a decision is made that will change life in Terra Nova forever. Lucas races to assemble the final pieces of his mystery device, in advance of the 11th Pilgrimage's arrival. Also, Jim and Taylor confront the colony's "Sixer" mole, Skye is reunited with a familiar face and Terra Nova prepares for war. Taylor and Mira must set aside their differences when they encounter a prehistoric enemy; Jim closes in on the mole. As Taylor searches for the "Sixer" mole within Terra Nova, Jim stumbles onto an old murder, for which Taylor is the prime suspect. Maddy starts interning for the colony’s greatest scientist, and her life is put in danger when she discovers a terrible secret. Meanwhile, Josh makes a deal with the devil in order to solidify his plan to bring his girlfriend from the future to Terra Nova.