Having followed Michael Burnham through a wormhole into the future, USS Discovery emerges at high speed above a planet surrounded by many large asteroids. The crew is unconscious, with Saru awakening first and rousing the bridge crew back to stations. Jett Reno explains that tidal forces in the wormhole similar to g forces knocked everyone unconscious. The ship is in an uncontrolled free fall as the crew races to regain manoeuvrability.
Discovery ploughs straight through an asteroid covered in trees and falls toward the planet. Approaching a glacier on the planet’s surface, Gen Rhys fires a graviton beam to soften the ice and cushion the impact. After hitting the ice, the ship’s deflector shields fail and the ship slams to a halt, jolting many crew members and throwing Lieutenant Keyla Detmer over a console. The ship rests atop the glacier, groaning from damage, with large chunks of ice resting atop the hull.
Tactical and both internal and long-range communications are down. Ensign Tilly reports that sensors are also down, leaving her no way to determine where or when they are. Reno points out that Terralysium, their supposed destination, was not particularly icy, indicating at the very least they are on the wrong planet. She also speculates that systems are down because of a ruptured plasma manifold from the crash; repairing it will require finding and fixing many damaged EPS relays and conduits. Saru notes that Discovery is unable to contact Burnham for the moment but that the crew remains together and alive and will search for her when possible.
As Saru surveys damage, Tilly tells him that the planet has pockets of atmosphere with higher levels of oxygen than elsewhere. The pockets are decagons, a ten-sided polygon, indicating they were constructed.
Tilly has also found signs of a populated settlement inside one of the pockets, reassuring Saru that their mission to stop Control from destroying all sentient life in the galaxy was successful. They encounter R.A. Bryce, who reports that a critical transtator in the communications system needs a complete rebuild, which he estimates will take at least six hours if the ship has enough rubindium.
Georgiou states that “somebody had to make sure he was dead” and informs Saru someone needs to clean the spore cube because there are “gooey bits” of Leland everywhere.
She insists that repairing the communications system should be a top priority in order to find Burnham, but Saru directs repairs on the EPS system to continue so the ship can regain flight capability and have defensive weapons.
Lieutenant Paul Stamets awakens in a chaotic sickbay, where he was taken after being impaled by a seven-inch shard of duranium alloy shortly before Discovery entered the wormhole. Hugh Culber says he would not have awoken Stamets from his medically-induced coma so soon, but that casualties worse off than him require the use of his biobed. Culber places him in a cellular regeneration chamber across the hall, where he orders him to remain for at least one full cycle, though healing the scar on his chest will require five cycles. The two kiss. Stamets says he is glad to have Culber back; Culber replies that it is good that Stamets is alive.
Meanwhile, Dr. Tracy Pollard sends away an alien crewman who has died. She then informs Detmer that her neurological tests are clear and she has no concussion, meaning she can return to duty. Detmer, however, is still feeling sluggish. She leaves sickbay, but does not acknowledge Culber as she walks out, leaving him confused.
In the ready room with Saru, Nhan, and Georgiou, Tilly reveals Discovery does not have enough rubindium to reconstruct the transtator needed to restore communications, frustrating Georgiou. However, the settlement Tilly detected has rubindium, along with other elements Tilly cannot identify. She adds that the fifty settlers have ships that appear designed for warp travel but do not have any dilithium. Saru and Tilly prepare to depart to barter for the materials they need, which includes getting a treatment in order to be able to breath the planet’s atmosphere. He leaves Nhan in charge of repairs and directs Georgiou to assist in fixing the EPS system.
In engineering, a groaning Stamets verbally spars with Reno, whose own back hurts following the crash-landing, regarding tracking down the ruptured relay, and the two reluctantly pair up. Inside the spore cube, Gene cleans up the remains of Leland.
Saru and Tilly, dressed in civilian clothes, depart the ship through an airlock onto the glacier. Tilly marvels at the strange locale, including the “giant hunk of planet hanging there in the sky,” and laments she does not have time to study the phenomenon. Saru calms Tilly, who is hurt that Georgiou thinks she is worthless, and says that they are introducing themselves to the future and that Tilly “makes a wonderful first impression.” The pair spot a dark figure in the distance who watches them before turning away.
On board Discovery, Nhan tells Georgiou that the ice visibly growing around the ship is somehow parasitic and that Nilsson and a team are studying it, but that its growth accelerates in the shade, meaning the ship will be “screwed” once the sun sets. Georgiou asks why Nhan remained aboard Discovery rather than remain in the past; Nhan replies that she felt a need to remain in order to honor Airiam, who “was a science officer but paid the price of a soldier.” Georgiou replies that she stayed aboard Discovery to avoid being placed in charge of Section 31 as she knew that in her words “bureaucracy is where fun goes to die.” The pair encounter Linus, who reports that the EPS grid on Deck Six has been repaired. Georgiou asks about Linus’s visual spectrum, and he states it is 74,000 nanometres. Nhan orders Linus to Deck Eight for further repairs, and Georgiou, with a mischievous look, volunteers to join him.
On the surface, Saru and Tilly follow the stranger and note that the floating rigs have visible blast marks, indicating someone wanted to shut them down. The stranger walks into a ravine, where he is transported away. Saru and Tilly follow and find themselves transported to a bar embedded high atop the cliff. The three Coridan men inside draw weapons on them. They reveal they saw the Starfleet ship crash but question whether Saru and Tilly are Starfleet officers; Tilly’s recitation of Starfleet code about officers’ conduct convinces them to lower their weapons.
One man identifies himself as Kal and says he believes the officers will help them with an unknown problem. He says the planet has no official name but that they are miners and call it The Colony. Os’ir the bartender warns that Zareh will have tracked Saru and Tilly to the bar. Tilly offers to trade some of Discovery‘s dilithium in exchange for the materials needed for a new transtator. Kal says they will require enough dilithium to power their vessels, fix other equipment and to barter at the Tellarite Exchange.
Aboard Discovery, Stamets and Reno have tracked down the final blown relay in a Jefferies tube, but Reno says her injured spine prevents her from accessing it. Reno offers to summon Nilsson to make the repair, but the ailing Stamets volunteers to crawl into the space.
In the bar, Kal says the transtator appears old. He uses programmable matter to construct a new device, which amazes Tilly. Kal tells her he always believed Starfleet would come to help and says once the colony is self-sufficient again, the miners can defend themselves. Os’ir tells Saru that Zareh is their courier, who delivers anything they cannot make or grow, “which is pretty much everything.” Suddenly, Zareh and several henchmen arrive before Saru or Tilly can leave. Zareh says they must be from Discovery, though he could find no trace of the ship in his database.
Kal, bluffing, tells Zareh they have been in contact with other Federation ships. Zareh says he detected high-energy gamma rays and gravitational waves upon their arrival and, after seeing their outdated technology, correctly deduces they are time travelers, surprising Kal. Zareh kills Kal painfully in retribution for having helped Saru and Tilly.
Zareh says he can do better at the Tellerite Exchange by breaking down the Starfleet officers’ equipment for parts. Saru demands to negotiate a reasonable settlement with Zareh, but Zareh insists they have no authority and that the most important thing was obtaining dilithium. He reveals that the parasitic ice is leaving Discovery with little time to get off the ground before it surrounds the ship and crushes its hull and crew.
Back on Discovery, Stamets approaches the damaged relay in the Jefferies tube. Nhan discovers that Georgiou did not join them on Deck Eight for repairs and is now missing. A sudden jolt of the ship leaves Stamets bleeding in the Jefferies tube.
In the bar, Saru and Zareh negotiate a deal and Zareh prepares to send Tilly back to the ship to retrieve the dilithium. He warns her that at night, the ice infests everything, and can even go down a person’s throat. Before she can leave, Zareh’s men capture Georgiou along the perimeter. He orders her shot, but Georgiou deduces that Zareh’s competitors likely also observed Discovery‘s arrival and are on their way and that Zareh is not strong enough to fend them off. Zareh shoots her on a low power setting several times before Georgiou and Saru team up to fight back. The pair kill Zareh’s henchmen, but Saru stops Georgiou from killing the disarmed Zareh. Tilly notes the sun has set, accelerating the ice’s growth on Discovery.
Via remote tricorder, Reno watches Stamets repair the relay. Culber arrives and chastises Stamets, but Reno tells him to set aside his anger so he can repair the relay. He does so, restoring power to Discovery.
Saru orders Georgiou to hand over her weapon, which she does reluctantly. He then promises to hand over Zareh’s vessel to the miners, and send them enough dilithium to power their own ships. He leaves Zareh’s fate to Os’ir, who gives him Tilly’s pack and sends him out to the planet’s surface. Georgiou also promises to kill Zareh if he returns to seek vengeance on the settlement. After Zareh leaves, Os’ir gives Saru a personal transporter and welcomes him to the future.
Back aboard Discovery, Bryce is able to repair the communications system with the new transtator. Defence systems are still down and sensors are only partially functional, but shields and other systems are coming back online. Detmer reports that impulse and manoeuvring thrusters are ready, but notes that Discovery was not designed to take off from a planet like this. The ship struggles to break free of the parasitic ice. An unidentified vessel approaches, prompting fear that it is one of Zareh’s competitors preparing to attack. Suddenly, Discovery is caught in a tractor beam that pulls it free of the ice. The ship hails them, and the crew is surprised, but relieved, to see Burnham, with long braided hair, on the other end. She reveals it has been a year since she arrived in the future.