The camera follows the path of a prehistoric dragonfly as it flies from Terra Nova all the way to the Sixers' tree camp. Meanwhile, Taylor is interrogating Boylan and accusing him of being the Sixers' source of information in the colony. Boylan admits to trading medicine with the Sixers, but never information. Taylor locks Boylan up with alarms blaring in his cell. Maybe he'll want to talk after a restless night's sleep.
Meanwhile, the colony is getting ready for the Harvest Festival, which celebrates Taylor's arrival in the past and the founding of Terra Nova. Zoe has been cast in the lead role of Commander Taylor. Meanwhile, Josh is frustrated because since Boylan's capture, the bar has been closed, and he can't get to his job.
Taylor sends Reynolds to lead a team to bring supplies to one of the colony outposts, and then brings Jim to Boylan. Taylor spiked Boylan's food with drugs, which will hopefully loosen the man's tongue. Taylor is called to deal with an issue elsewhere, and Boylan begins babbling about something buried beneath Pilgrim's Tree, all the while thinking that Jim is Taylor.
Jim scans through maps to try to figure out where Pilgrim's Tree is. Malcolm tells him that the location was where Taylor first made his camp in the new world. Jim digs into the ground beneath the tree and discovers a skeleton. He brings the bones over to Elisabeth, explains that Boylan led him to where it was buried, and asks her to identify the body. Elisabeth says that the man was middle-aged and the break in his ribs may mean that he was shot and left for dead. Also he's missing an arm, which may have been taken by hungry dinos.
Tipped off to the convoy, the Sixers attack Reynolds and the rest of the soldiers and steal their supplies. Meanwhile, a dragonfly interrupts rehearsal of the Harvest Festival play and a soldier swats at it. Maddy notices that there's a chip of some kind attached to the bug's leg. Malcolm says that the Sixers must be using the dragonfly to ferry information like a carrier pigeon. He just needs to figure out what's luring the bug back and forth. They can't just let the bug go, because its wing was injured.
Reynolds returns to the colony and says that the Sixers knew where they were going to be. Since Boylan was locked up during this time, he can't be the mole. Taylor reluctantly orders Boylan to be let go. Meanwhile, Elisabeth has discovered something odd about the body. Everyone who has gone through the portal has residue from the time displacement, which means that one can look at a colonist's DNA and identify which pilgrimage they arrived on. However, the body doesn't match any of the known pilgrimages, and seems to have gone through the portal between the second and the third.
Jim tells Boylan about the body buried at Pilgrim's Tree. Boylan explains that he used to be a guard in the early days of the colony and he was out on patrol when Taylor suddenly told him to help him bury the body. Boylan claims that he didn't recognize the dead man. Only that Lucas got the man to pass through the portal somehow.
Malcolm finds out what Elisabeth has been working on and informs Taylor. Jim says that he found out about the body via an anonymous note left on the Shannon home's door. Taylor shrugs it off, saying that it was probably a Sixer who falsified his DNA records to hide a criminal past.
Malcolm discovers that the dragonfly is being lured by sound, and he's figured out the exact frequency the Sixers are using to call the bug between locations. If they can find whatever's emitting the frequency in the colony, maybe they'll find the mole. And Malcolm has surgically repaired the dragonfly's wing, making it able to fly again.
The Harvest Festival play begins, and Jim notices that Taylor's commanding officer, General Philbrick, is portrayed as only having one arm. Jim and Elisabeth wonder about the true fate of Philbrick, as the news reports stated that he was killed in South America but no body had ever been found. But then Taylor arrests Jim for spying, as the dragonfly had headed straight for the Shannon house. However, Taylor has anulteriormotive for getting Jim out of the picture: he doesn't want Jim to find out the entire truth behind Philbrick's death.
Jim is insistent, however, and Taylor finally recounts what happened. Philbrick arrived at Terra Nova to relieve Taylor of his command of the colony, and Taylor refused to give it up, even at gunpoint. Taylor killed Philbrick because he didn't want the same forces who nearly destroyed Earth to be in charge of Terra Nova as well. They'll strip the world of its resources and take everything back to 2149.
Jim counters that the journey to Terra Nova is only a one-way trip to the past. However, Taylor confesses that his son Lucas was working on a way to change that. Afraid of what the future will do to the past, Taylor destroyed all of Lucas's work and Lucas fled from the colony.
Taylor found his son, but then Philbrick came through from the future. He was asked to leave his position as the colony's leader but refused. Philbrick attacked him and Taylor defended himself, killing his mentor. When Lucas also tried to attack him, he banished his son from the colony forever.Lucas still hasn't given up on his research and has left his equations all over the area for Taylor to find. Taylor wants to keep the colony from knowing the truth, as the colonists may lose hope that what they're doing has meaning. Taylor then sets Jim free, knowing that Jim would fight for the colony no matter what.
Jim is reunited with his family and Taylor tells Malcolm that Jim isn't the mole. Jim's sonic blaster just emitted the same frequency as the one the dragonfly was trained to follow. Malcolm doesn't actually buy it, thinking that Taylor planted a sonic device at the Shannon house.
Back at the festival, the colony greets its newest member as Taylor presents a baby to the crowd. He also reminds the crowd that they are all on an amazing journey together. Fireworks are sent into the sky, and Lucas spies them from miles away.