Commander Taylor immediately grants sanctuary to little runaway Sixer girl Leah Marcos. He's even prepared to fight off a return claim, but Miera gives in suspiciously easily when Leah chooses to stay in Terra Nova. Jim lets her stay in the Shannon home, at least until a permanent foster family is selected. Jim can stop Leah just before she could flee the camp with a mysterious item she dug up from Mira's former home. Taylor mistrusts her story she had to fake having ran away because her kid brother is kept hostage, but Jim sets out to the Sixers side. He's captured and released with assurances the boy was never in real danger and a vague claim the Sixers serve the real, secret present-world purpose of Terra Nova, after an invitation to change side. To Josh's mild amusement, Maddy fails her medical training apprenticeship, being unable to stand disgusting symptoms.
When an orphaned "Sixer" girl comes to Terra Nova seeking asylum, Jim and Shannon are at odds if they can trust her; Mira plots to reclaim a valued possession; Taylor begins to suspect there is a traitor in his midst and Reynolds admits his feelings for Maddy.
- The guards on the walls of Terra Nova notice something stirring in the woods. It's not a dino ... so it must be a Sixer. So Washington and her troops give chase and soon discover a tiny blonde girl. Back at the medical lab, a doctor tries to stick the girl with a needle and the little urchin strikes back. "She's terrified," Elisabeth says. "I need to get everybody out of here." So everybody, including Taylor, leaves. Elisabeth successfully coaxes the girl out from underneath a table and gently examines her. The girl, an orphan, explains that she dropped her bag in the jungle while being chased. Taylor then reenters with food. The girl is ravenous. "I only get scraps," she says. "That's why I ran away."
Taylor then identifies the girl as Leah. He used to know her family before they all defected to the Sixers side. Later, Taylor explains to Jim that he sees Leah as an opportunity to get intelligence on the Sixers. Elisabeth then volunteers to take in Leah. Jim is unsure and Josh is just plain unhappy as he will have to give up his room. But the Shannon family pulls together to warmly welcome its new, shy houseguest. CUT to the jungle, where Washington and another soldier hunt for Leah's bag. Suddenly, they are attacked by Sixers. A total badass, Washington singlehandedly takes out two or three Sixers before Mira appears and subdues her. "Still doing Taylor's dirty work?" Mira sneers. "What did you do with her?" We assume she is asking about Leah.
Meanwhile, Josh has been left in charge of watching Zoe and Leah while Maddy heads to the hospital to apprentice with her mother. Jim and Taylor walk through the market when the alarm begins to sound. Sixers -- lots of them -- are approaching the front gate. Mira pushes a restrained Washington to the front as trade bait. "You have something that belongs to me," Mira says. "I want her back." Taylor says he will bring out Leah and let her decide ... if Mira releases Washington. Mira agrees and Leah is soon brought to the gate by Jim. "Tell them you want to come home," Mira says. "Speak!" Leah flinches, explaining that she ran away and doesn't want to return to the Sixer camp. "Keep her then," Mira practically spits. "She's nothing to me." Before Mira can leave, Taylor warns her not to threaten Terra Nova again. "Next time I go to war," Taylor growls.
Taylor then makes nice with Leah, suggesting she might look at a map and identity the various Sixers campsites. So all appears well. Leah looks happy to be with such a loving family and a caring community. Later, Taylor and Jim go over a list of people who might have seen Leah and reported the news to the Sixers. In other words, they are looking for the mole inside Terra Nova. Taylor then heads out with Jim to interrogate a scientist named Rob arrived at Terra Nova with Mira, but didn't defect with her. Malcolm arrives after a few pointed questions to defend his associate. "This is guilt by association," says a furious Malcolm, noting the conspicuous lack of lawyers in Terra Nova.
Later that day, Washington and Jim investigate a robbery inside Terra Nova. A piece of the floor has been removed, revealing a hidden safe. The current owners had no idea such a hideaway existed. And who used to live in the place? Mira, of course. "We need to find Leah right now," Jim tells Washington. CUT to Leah, who is sneaking through Terra Nova on her way to the fence. Suddenly, Jim sneaks up behind her. "What did you take from that couple's house?" he gently asks. Turns out that Leah is almost certainly a spy sent by Mira, who then made quite a show pretending to want the little girl back. The item that Leah took from Mira's old house is a container of some kind. But what kind?
Leah claims not to know. "Mira's got my brother and she said she would hurt him if I didn't steal back that box," the girl says. "I'm telling the truth." Understandably, Taylor and Jim are skeptical. Leah is then taken into custody. Taylor refuses to consider Jim's suggestion that they send a few men to check out Leah's story -- just in case. A little boy could be in danger, but Taylor refuses to risk men without more evidence. Back home, Jim finds a note from Leah that says, "Sorry, I had to." This convinces Jim that Leah's brother, Sam, really IS in danger. Looks the big guy is thinking about defying Taylor.
In the meantime, Reynolds very politely asks Maddy if he can court her. She is flattered and tells Reynolds all about her disastrous day at the hospital. Apparently, Maddy doesn't have the steel stomach of her mother when dealing with blood and wounds. CUT to Jim, who sneaks through the jungle looking for the Sixers. Within seconds, he is SNAGGED in a trap and soon finds himself hanging upside down a few yards off the ground. Naturally, a Slasher dino emerges and begins LEAPING at the hanging dad. Suddenly, the Slasher is hit with an energy blast. Sixers emerge from the tree line. Uh oh.
Sure enough, Jim awakens sometime later with a bump on his head. He is inside the Sixer camp and facing down Mira. "The boy was never in danger," Mira explains. "I just needed to motivate her." Jim asks what is in the box that Leah attempted to steal. Mira only smiles. Jim then asks, more or less, why she is so generally unpleasant. "Taylor has pissed off some very important people back in 2149," Mira says. "They want him gone." Mira goes on to explain that Terra Nova isn't about starting over as Taylor says -- not anymore. Exactly what Taylor's motivations might be, however, she refuses to detail. She also says that "they" will let her see her daughter again once her mission is complete. Jim asks, "Who's 'they?'" Again, Mira refuses to answer. Instead, she releases him.
Back at Terra Nova, the doors to Leah's cell suddenly open ... and Sam runs inside. The two siblings embrace. Jim watches them, smiling. Apparently, Mira allowed Jim to bring back the boy and reunite what is left of Leah's family. Later, Taylor admonishes Jim for defying orders -- but too hard. "Did she say anything I should know about?" Taylor asks in reference to Mira. Jim dances around the question. He clearly has newfound suspicions. We then find out that Maddy is no longer a hospital apprentice and a single woman in camp has expressed an interest in bringing Leah and Sam into her home.
At the end of the episode, Leah gives Sam a huge hug. "Thank you," says the girl.