It's the colony's founding day. Josh asks dad Jim to check up on Boylan, whom commander Taylor grills mercilessly about the Sixers' mole, then uses a truth serum overdose. Thus Jim hears about a secret buried under the pilgrims tree, which Malcolm knows to be Taylor's alleged first home as colony founder. There Jim finds a corpse, which misses an arm, just like missing general Philbrick. Meanwhile a smashed giant dragonfly is found to be chip-bugged by the Sixers. Malcolm repairs it to trace their mole's communication line. When it enters the Shannon home, Jim is arrested as suspect of being Mira's mole, but he's soon released after hearing Taylor's story about his own son Lucas's part in the ignoble true motives for founding the colony.
As Taylor searches for the "Sixer" mole within Terra Nova, Jim stumbles onto an old murder, for which Taylor is the prime suspect.
- We follow a prehistoric firefly outside of Terra Nova and into the Sixer camp, where it lands on Mira's hand. "What do you got for me today?" she asks. Is the fly the spy? Taylor, meanwhile, interrogates Tom, who admits to having traded with the Sixers. He did NOT, however, give them inside information. Taylor believes Tom is withholding -- so he turns on a blaring siren inside the prison cell and slams shut the door. Torture.
The Shannon family, in the meantime, gets ready for the "Harvest Festival," where a play celebrating Taylor's arrival is apparently staged each year. And, for some reason, Zoe is portraying Taylor in the play. Josh then pulls aside Jim, asking his dad to check in on Tom. "I'll see what I can do," dad promises. Later, Jim visits Taylor inside Tom's cell. Tom isn't looking good. He is barely conscious. "He did shoot a Sixer and save your life," Jim says. "You really think he's a Sixer?" Taylor doesn't seem to care. After Taylor leaves, a drugged Tom begins babbling about something being buried by "Pilgrim's Tree" -- something that would destroy Taylor. Jim is intrigued.
Jim then heads to Malcolm, who explains that Taylor lived in what became known as "Pilgrim's Tree" when the commander first arrived at Terra Nova. Malcolm even gives Jim coordinates. So Jim head to the tree -- alone -- and starts digging. He finds a skeleton. Later, Elisabeth examines the body and deems it a middle-aged male who has been dead for four to six years. The man is missing his right arm. Did Taylor do it? "I think Taylor would do anything if he thought it was in the best interests of the colony," Jim says.
CUT to Reynolds on patrol in the jungle. Suddenly, a tree falls in the road -- and Sixers ATTACK. A furious battle ensues in which the Sixers quickly get the upper hand. They steal all the medicine and food from the convoy. Back at Terra Nova, Maddy directs the school play when the giant dragonfly suddenly appears. One of the soldiers BATS the bug with his weapon -- and Maddy notices that it is equipped with a microchip. Later, Malcolm explains to Taylor that they have found the spy's delivery device -- an insect. "They must have found out how to lure it back and forth between locations," Malcolm explains. Washington then enters with bad news: the convoy has been hit. Washington explains that she put together the convoy AFTER Tom arrested. The bartender couldn't possibly be the Sixer spy. A grumpy Taylor tells Washington to let the prisoner go.
Back at the hospital, Elisabeth discovers that the dead body found at Pilgrim's Tree didn't come through time on an "official" pilgrimage. Instead, the victim arrived between the second and third pilgrimages. Jim then visits Tom, who says he helped Taylor bury the body -- but doesn't know what happened to the man or who he might have been. Tom explains that Taylor blamed Lucas for the mystery man's death after summoning him through time. "That was the last night anyone saw Lucas Taylor," Tom finishes. CUT to the hospital, where Malcolm discovers the mystery skeleton. "I don't like having secrets in my own lab," Malcolm tells Elisabeth. Malcolm then announces he is getting Taylor.
Moments later, Malcolm, Taylor, Elisabeth and Jim are gathered around the skeleton. Jim lies, saying he was alerted to location of the grave by an anonymous note left at his door. Taylor, also lying, declares that the body must be an errant Sixer. Now Jim is REALLY nervous. The next day, Malcolm discovers that the dragonfly is being summoned and sent via a sub-sonic signature. He suggests to Taylor that they release the insect -- whose wing has been surgically repaired -- and follow it right to the spy sending out the signal.
Festival time. Malcolm releases the bug and follows it on a handheld monitor while Terra Nova's children put on their play to honor Taylor. Proud parents Jim and Elisabeth watch as Zoe plays Taylor ... and shares dialogue a young boy who plays a general who is missing his right arm. Jim and Elisabeth put two and two together. Jim theorizes that the general came back to Terra Nova to relieve Taylor of his command. Just then, Taylor appears -- and announces that he is putting Jim under arrest. Why? The dragonfly went right to the Shannon house. "You're the spy, Shannon!" Taylor barks.
So now it's Jim's turn in the interrogation cell. It soon becomes clear that Taylor doesn't really believe that Jim is the spy. Rather, Taylor just wants the cop to drop his investigation into the dead body. Jim refuses the deal, vowing to uncover the truth. "Why'd you kill General Philbrick!?" Jim demands. Taylor angrily explains that he did kill the general. Why? Because the same people who sent the general to relieve Taylor also sent the Sixers. And these people -- these "vile people" -- just want to plunder Terra Nova like they did the Earth. It was never a new beginning, but the same old story.
Taylor wants to defend Terra Nova and so these future folks want him dead. And the exposition doesn't stop there. Taylor explains that Lucas was working on a way to open a convenient pathway between past and future. "He was on their side from the get go -- he was working to make the portal go both ways," the commander says. When Taylor found out, he destroyed all his son's work. Days later, Lucas went AWOL. Taylor followed his boy and watched in amazement as the general suddenly appeared from the future in a ball of electricity. Taylor shot the general ... but couldn't pull the trigger on Lucas. "You're a traitor," Taylor told his son. "There's no place for you in Terra Nova. I never want to see your face again." That was the last time Taylor saw his boy -- five years ago. But Taylor does see Lucas's calculations on rocks left behind to taunt dear ol' dad.
Taylor then releases Jim -- and apologizes for "playing rough." Explains Taylor: "My own son is out there formulating an equation that will allow his friends on the other side to have their way with our home. Would you bow? Would you let those people do to Terra Nova what they did to the Earth they left behind? Or would you fight?" Jim answers: "I would fight. I will fight." Outside, the festival continues unabated. Taylor then admits to tuning the power charge on Jim's gun to attract the dragonfly. Later, Taylor addresses the assembled population, telling the crowd that "we're all in this together ... You're my friends, my family, my loved ones." Fireworks explode in the sky.
CUT to the jungle, where Lucas sits at a campfire. He watches the fireworks from afar.