Crichton and Aeryn have trouble navigating the tunnels, but are able to find Chiana by her voice. She’s hanging suspended from a strange device, surrounded by the ragged people that grabbed her.

After drawing their weapons, Aeryn and Crichton burst into the room to free Chiana. She doesn’t want to be freed, though – she’s decided to join the gang, and the device was merely part of an initiation rite.

As Chiana storms off, Aeryn, Crichton and the gang examine each other. The gang’s leader is named Molnon, and he quickly pronounces Crichton and Aeryn "aged" and "historic."

Aeryn finds Chiana sampling the gang’s local brew, and returns the lifedisk to her. Chiana’s not quite willing to talk about her brother’s death, and tries to distract Aeryn by showing her around.

She also tries to convince Aeryn to stay with her, at least for the gang’s upcoming "gathering".

As he searches for Chiana, Crichton senses an unseen presence passing by. He also encounters Molnon and a despondent gang member named Das, who is muttering about "the Lost Ones."

Crichton follows the two gang members to the gathering, where he joins Aeryn and Chiana. The gang has met in a cavern at the edge of a deep sinkhole.

A baby has been born, Molnon announces, and the clans are gathering. It’s time to celebrate.

"Way back," he recounts. "The ancients dug the royal tombs. But the surface is full, and the ancients leave. Now we alone – but we live . . . we take the stone."

Singing a low tone, a gang member throws himself into the sinkhole. Three others follow in quick succession, and each of their falls is broken by cushion of energy.

Aeryn quickly recognizes the energy as coming from a sonic net – a technology that the Peacekeepers use as safety equipment in aerial training. The sound the jumpers made has cushioned their fall.

Another gang member – Das – leaves a very pregnant woman behind and makes the jump. He doesn’t hold the tone, however, and his body smashes into the rock floor with deadly force.

The others treat it as the natural conclusion of the ceremony. "Das takes the stone," Molnon announces.

Chiana looks over the edge. "Drell," she says, "I gotta do that."

Chiana talks with the pregnant woman, whose name is Vyna. Crichton wants to talk to Chiana – and if necessary drag her back to Moya – but Aeryn tells him to leave her alone.

"If you try to force her to leave," she warns Crichton, "she will stay here just to spite you."

Molnon shows Chiana how Das’ body will be prepared and buried. She’s amazed he isn’t broken up at his best friend’s death, but Molnon explains that taking the stone brings the gang so close to death that they no longer fear it or worry about it.

Aeryn and Crichton encounter Vyna, who is drinking heavily. She tells them that when her baby comes, Chiana wants to jump, and that she’s given Chiana her blessing.

Chiana doesn’t want to leave, and she doesn’t want Crichton’s help. "At least they get to live before they die," she tells him. "That’s what I want to do."

Aeryn refuses to help Crichton talk Chiana out of it. "It’s Chiana’s choice," she says.

"Great." Crichton replies. "That’s just great, Aeryn. You know, I hope if I ever decide to jump in front of a bus you’re not the only one there."

Crichton goes to look for Molnon. On the way, he senses someone following him again, and grabs her.

It is one of the "Lost People" Janixx is horribly disfigured, and says that everyone over the age of 22 shares her fate if they do not take the stone.

Before fleeing, she also says that Das claimed he knew why this happened – that the cliff is the key. Crichton notices that she left a piece of skin on him when he pulled her into view.

He finally finds Molnon, who admits that he is nearly 22. Crichton demands to know why Molnon is dragging Chiana – who isn’t going to die anytime soon – into their ritual.

Molnon refuses to answer unless Crichton tastes one of the gang’s hallucinogenic mushrooms – a fungus so potent that one out of every four lobes kills the person who chews it.

Crichton takes the dare. After he chews a lobe, Molnon tells Crichton – figuring the human won’t remember after tripping on the mushroom – he’s afraid that the next time he jumps he’ll be killed, so he wants Chiana to take his place.

Crichton trips out and collapses.

He does remember, though, when he returns to consciousness. He’s not quite clear on all the details, but he’s fairly certain he convinced Molnon to get Chiana not to jump.

As he picks himself up and goes to see "if this Excedrin headache was worth it," he asks Aeryn to scan the skin sample from the "Lost One" and send it to Zhaan. Hopefully she can figure out what the teens are dying from.

As he waits for Chiana, Crichton fills a hypodermic with a knockout drug. When she arrives, she’s thrilled to see him – she says Molnon has told her about their conversation.

She’s still jumping. She doesn’t believe Molnon’s using her.

"I want to jump," she says. "I have to."

Crichton remains calm long enough to inject her with the hypodermic. As he starts to carry Chiana’s unconscious body to the pod, though, Aeryn stops him.

"If Chiana really wants to," she tells Crichton, "she’ll find a way to kill herself." The only way to help her is to let her work through her feelings here on her own.

"When did you get so insightful?" Crichton asks.

"I understand loss," Aeryn answers.

"So do I," says Crichton.

Rygel has all his new treasures hung up on display. He’s busy admiring them when they begin throwing themselves off the walls.

Zhaan has discovered that the tissue samples show signs of radiation poisoning, but the normal radiation level is too low to account for it. It’s possible that the cliff chamber is somehow amplifying the exposure, though.

Moving the gang out of the caves could save their lives – but it would also eliminate their reason for taking the stone.

Rygel confronts Zhaan and D’argo, accusing them of faking a curse to get him to return the artifacts. They have no idea what he’s talking about.

Crichton and Aeryn find Vyna, who is in the throes of childbirth. They tell her about the radiation, and ask her to convince the clan to stop the jumps and move.

She refuses. It’s the way of the clan, and besides, she doesn’t want to get old and worn out like Crichton and Aeryn.

On the cliff, Chiana is preparing to jump. Crichton and Aeryn arrive, and Crichton orders her to stop.

He tells the gathering about the radiation, and that it’s possible to live a longer life on the surface. Molnon mocks him, but Crichton steps up on the platform and grabs him.

Confronting Molnon’s fear of jumping head-on, he offers to take the stone with him. Molnon consents to a vote of the clans on moving to the surface.

"You satisfied?" Chiana asks. "You can’t help me."

Aboard Moya, Rygel puts up his best display of bravado, but a fusillade of sharp objects quickly convinces him to return his loot to the graves.

Crichton asks Molnon how the vote went. All the clans voted to stay – they want the stone – and he’s already given Chiana a head start to the cliff.

Crichton knocks Molnon unconscious and goes to Chiana.

After he assures her he’s just here to talk, the two of them stare at the cliff together.

"Never had any courage," she tells him. "As a kid Neric gave me everything. I just followed him."

"I’ve got to see if I can do this, Crichton."

"And if you die?" he asks.

She turns her back on the cliff and jumps. She sings the tone steadily as she falls, and the sonic net catches her.

Even Crichton is swept away in the moment. "You did it!" he yells.

She did it. She’s alive.

Crichton and Aeryn wait as Chiana buries the lifedisk. Meanwhile, Rygel struggles with returning the last of the treasure.

As Chiana finishes, Crichton joins her. "Molnon was right about one thing," she says. "The jump – it was incredible. You should have tried it."

"I’m too old," Crichton replies. "It’s time to go."

Chiana pauses a few more moments, thinking

"Let’s get out of this dead place," she finally says.

As they go, they strike the gang’s jumping poses for each other.