Picking up in outer space where Graham and Ryan are rescued by a spaceship piloted by Angstrom. She says she didn't see anyone else when she picked them up. She tells them she's found the planet even though it's off orbit. Ryan and Graham have no idea what she's talking about and try to get her to turn around to find Yaz and The Doctor
Yaz wakes up in another spaceship where The Doctor is arguing with Epzo about the ship's condition. The Doctor wants Yaz back in the medipod and Epzo is wondering how a planet goes missing. The Doctor spots the planet on the screen. Epzo wants to know how it could've moved. The Doctor asks what its name is. He tells her the closest translation is "Desolation."
Epzo doesn't think he can get the ship to the planet because he used up his fuel rescuing her and Yaz. The Doctor advises him to jettison the rear of the ship in order to make the landing on the planet.
Angstrom and the men have landed on Desolation. Angstrom heads out to surveil the atmospheric data. Ryan and Graham discuss their options and decide to follow her.
The Doctor is directing Epzo on how to bring the ship in for a crash landing. When they enter the atmosphere, their landing path is practically on top of Angstrom, Ryan, and Graham.
In the aftermath, The Doctor and Yaz reunite with Graham and Ryan. She promises to find them a way home. Angstrom greets Epzo as well. Apparently, they're competitors and the only ones left. An alarm starts sounding and Angstrom and Epzo lead the group to a tent in the middle of a desert.
Graham asks how they can understand Angstrom and Ryan and The Doctor finds that they've all been implanted with universal translators by the medipods they recovered in.
Entering the tent, she introduces herself to the man waiting there and then demonstrates that he's a hologram. They find out that 4000 competitors started the rally and Epzo and Angstrom are the last ones left. The hologram sets their last task and states that the winner will win a life of luxury for themselves and their clan while the other will be left stranded. They must cross the terrain and find the Ghost Monument in one day's time.
Epzo and Angstrom set off and The Doctor pesters the hologram for details such as what the Ghost Monument looks like. He brings up an image of the T.A.R.D.I.S. and then everything around them disappears with him, leaving them exposed in the desert.
They follow the rally racers to the water where Epzo is holding Angstrom at blaster-point in order to take the single boat out on his own. The Doctor points out that the rules of the game stipulate there is no killing or injuring allowed. When Epzo tries to tough-guy it, she paralyzes him with her pinkie.
Apparently, the boat doesn't work so Graham volunteers to take a look at it with Ryan. The Doctor tests the water and discovers that it is full of flesh-eating microbes.
Graham and Ryan discuss Grace's passing and what she'd say if she was there. Graham tries to connect with him but he rejects him. Looking at the engine again, Ryan says it looks like a battery and hypothesizes that it's solar-powered.
Yaz is talking with Angstrom about her home planet when Angstrom suddenly shuts down. The Doctor announces that the boat's ready to go.
On board the boat, The Doctor tries to figure out what's wrong with the planet, why it's so hostile, and where its inhabitants went.
Epzo shares some hard truths about his life. Once he falls asleep, Angstrom explains that this race is the only way she can save her family from the genocide on her home planet. The Doctor advises them all to rest until they get to the other side of the water.
Graham wakes Ryan up when they get to the other side of the water. They approach the ruins and The Doctor asks again where the planet's inhabitants went.
Angstrom and Epzo head off on their own, leaving The Doctor and the Companions to explore on their own. They find themselves surrounded by robot guards. Ryan tries to fight back with one of the robot weapons but only makes things worse. The Doctor sets an electromagnetic pulse and fries them all for a short period of time.
Epzo's been shot but rejects Angstrom's help. The Doctor and the Companions find them and lead them to the center of the sniper-bot command source. She opens a hatch and they head down. Ryan isn't impressed with the ladder they have to navigate.
They find tunnels down below that run under half the planet. Graham notices scorch marks. The Doctor finds a big locked door and opens it with her sonic. The group investigates the rooms behind the door. Epzo doesn't care so he goes to take a nap.
The rest of the group finds a map projection that shows a way to the Ghost Monument site which is much faster than overland. If Angstrom leaves without waking Epzo, she could easily win. Next, they find a room with writing all over the floor. The Doctor interprets it as a last testimonial from the scientist that were imprisoned there by the Stenza.
Meanwhile, Epzo is being attacked by a cloth creature and Yaz and Ryan discover that the robot guards are watching the hatch they came down.
The others rescue him by cutting the cloth creature from him and the robots attack. Trapping the group down below, the robots shut down the air so they find another hatch which leads them into an acetylene field where a swarm of cloth creatures attacks, speaking their worst fears aloud to distract them.
The Doctor signals the group to dig down into the ground with their feet and then gets Graham to grab Epzo's special cigar which he throws into the air and The Doctor ignites with a snap of her fingers, lighting the acetylene in the air and incinerating the cloth creatures.
The group emerges from the ruins in the morning and approaches the Ghost Monument site but the T.A.R.D.I.S. is nowhere in sight.
Epzo and Angstrom enter the final tent together and demand to be recognized as dual winners. The hologram initially refuses but relents under Epzo threat to hunt him down. Once the winners are declared, they are teleported off the planet but leave The Doctor and Companions behind.
The Doctor despairs and the Companions try to reassure her that things will work out. As they talk, the sound of the T.A.R.D.I.S. can be heard and it begins to materialize nearby. The Doctor activates her sonic to help and runs to greet her ship. They all enter a newly designed ship and The Doctor starts it up to head home.