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No human has been as far out as Pluto, but when our team of astronauts lose contact with Earth after only a few months, things start to get weird. We open with Gilda and Ray discussing not having heard back from Earth for 3 weeks, despite missing a crew-retrieval window. The Plutonian crew have no way of leaving the dwarf planet themselves. Ray chides Gilda for becoming emotional over the unexpected delay.
Later, as Clark and Mattie work to repair a circuit board, they discuss Clark witnessing the falling of the last tree on Earth. Matti waxes reverentially about how since their extinction trees have become mythical. Clark, however, is unmoved by his childhood experience and Mattie says that seeing such a rarity was wasted on him. Mattie leaves and Gilda enters. Gilda chides Clark for not cleaning the wall, which is marked with a large, dark “X.” They argue about whether she asked him to clean it days ago or weeks ago. Clark argues that he can’t work because he’s in a union and his contract is expired. Gilda tells him to call the union then; of course he can’t because communication with Earth has been silent for months. She accuses him of being the reason comms are down because he is the comms specialist. He asserts that the messages are being sent and received, it’s just that no one has answered in 6 months. Gilda presses that there is no way that the space program forgot about them or that the entire human population just died, rather it is more likely that the comms are just not working. At a stale-mate, Clark agrees to clean the X and Gilda leaves.
Ray talks to Clark about birds. He blows his bird whistles and recounts a memory from his childhood of the day all the birds on Earth died. Clark suggests they play a game to lighten the mood and insists on Guess Who because Ray always beats him at chess. Ray recounts his previous experiences as an astronaut, landing on and launching from celestial bodies such as Mars and Titan. He resents being having to “ferry a bunch of green scientists” to Pluto and then wait for someone to pick him up. He postulates that the Pluto mission is just a tax write-off anyway and they only send undesirables there – the new, the old, and the British – whereas Americans get to populate Mars. We learn that all the animals have died when Ray tries to describe how real meat used to taste. After their game, Ray confides that after one of his missions, “maybe even this one,” he will refuse to return to Earth.
Gilda eats cereal in the dark and listens to a noise from above. Mattie sees her and asks what she’s doing. Mattie checks above and says there is nothing there but the oxygen and water systems machines, aka “the girls.” Gilda asks her to run tests on them the following day. We learn that Ray has died and Gilda asks Mattie why no one ever corrected her mispronunciation of Ray’s surname. Mattie answers that Ray thought it was funny. As Mattie describes her fear of never being picked up, she confesses that she would rather kill herself than to be stranded there forever, slowly losing her mind. Gilda admits to increasing feelings of anxiety and in response Mattie suggests masturbation would help her relax.
Mattie asks if Gilda has anyone waiting for her back home – Gilda answers that her mother died of dementia before the mission departure. The conversation switches to Gilda’s interests: she says she likes to take recordings of the sound on the surface of Pluto and listen to the “nothingness” in the dark. It’s a respite from the constant hum of the machines in the base. After a beat, Mattie tells Gilda that a month before he died, Ray started seeing things that weren’t there. He said he saw a girl, about 5 years old, with a scar across her mouth in the shape of an “X,” looking at him through the window. Mattie recalls that he kept asking, “What happens when she gets inside?” After Mattie leaves, Gilda puts her headphones back on to listen to the nothingness but suddenly the manic voice of a little girl issues from her laptop, cackling and speaking gibberish.
Out of boredom, Clark, half dressed, bounces a ball against the wall. Trying to focus, Cole asks him to do that elsewhere. Clark asks if Cole is doing math for fun and then comments that his math is wrong anyway. He offers to write Cole an algorithm in exchange for his laser pointer keyring and Cole agrees. Clark asks what factors to consider and Cole reveals that he is trying to figure out how much time has passed since they’ve been gone because he noticed that the digital clocks have been malfunctioning. As they watch the clock on the wall the time jumps backward. He says all the digital time keepers are doing the same thing so the only way to find the real current time was by retrieving Ray’s analog watch, which he took from Ray’s body in the freezer, but it ended up being broken anyway.
Gilda bandages Ray’s bloody arm after a failed suicide attempt. He asks her not to tell the others and she agrees. He bleeds on his photographs and they quickly clean them. She asks why he doesn’t just look at pictures online and he explains that it is more meaningful to have something you can touch. But also, the photos remind him of a time “when space travel meant something. When people cared.” Gilda tries to argue that people still care, but he counters with, “No one gives a damn. Earth is pissing its last and everyone’s just looking at their fucking shoes.” Gilda asks if she needs to watch him going forward. He doesn’t answer.
Ray sits alone, weeping and tearing his photographs to pieces. He hears a fluttering, then a whistling. He blows the whistle of the nightingale, then follows the sound of the bird up the ladder where “the girls” are. Cooing to the bird, Ray returns with his hands cupped only to find them empty. The clock glitches, the cupboard opens, and crawling out backward is the little girl with “X” carved across her mouth. Ray stabs at his neck with his penknife, then paints an “X” on the wall with his gushing blood. The little girl watches.
Mattie vomits into her EVA helmet. Gilda is not sure that Mattie is real and asks Mattie to tell her that she is there to take them home. Mattie says, “I’m here.”
Gilda tries to describe to Clark and Cole what just happened. She says she first saw Mattie out the window. Gilda couldn’t see Mattie’s face because of the reflective surface of the helmet, but she meets her at the airlock. She says she didn’t let Mattie in but that she got in still. Gilda says Mattie threw up in her helmet and Cole asks if it had a smell, but she doesn’t remember. She says that Mattie tells her it’s weird that the others are sleeping since it’s the middle of the day by Universal Time. Gilda finishes her story by insisting Cole and Clark had come in and asked Mattie questions themselves. She tries to remember what they asked Mattie. Gilda says Mattie only wanted to eat cereal after the 6 month journey and that she saw the last tree fall. Clark corrects her, “That’s my story.” Cole believes Gilda has gone crazy and demands where the spaceship is if this Mattie did indeed come to rescue them. They split up to search for it.
They don’t find anything yet Gilda keeps insisting it happened. Cole returns limping and tells her to stop talking to him lest she implant “false memories.” They continue to argue. Cole snaps and grabs her by the throat, forcing her to the ground. Clark pulls Cole off her but he presses, “She is putting our sanity at risk which is putting our lives at risk.” Only then does he realize he is limping. Cole demands to know what they did to him, but they gently remind him that he has cancer in his spine and keeps forgetting. He refuses to believe them and keeps arguing. In the course of conversation he forgets again and again. “YOU’RE LYING TO ME” he rages. Blood starts oozing from his ear and he collapses.
After Cole dies, Gilda and Clark scramble to remember events. Their minds cannot keep memories straight and they repeatedly misremember past events. Eventually they devolve into speaking gibberish. At some point they are able to at least be present. Clark wishes he could go back and be nicer to Gilda. He bemoans his imminent death, telling her, “I’m sputtering out. … My body’s catching up with my brain.”
Gilda is left all alone after Clark’s death. She hallucinates many terrifying things – the legs of a small child dangling from the hatch above, Ray’s bleeding corpse watching her from outside the space station, and an enormous nightingale gasping for breath as it bleeds out.
The little girl crawls out from the cupboard again. This time there is no scar across her lips. The girl excitedly tries to get Gilda to play hide and seek with her. Gilda has had a daughter, Mattie. Little Mattie runs off to get a pencil to measure her height on the wall but Mattie returns as an adult. Gilda is confused about the sudden shift in time, but tries to relax into the new scene. She tells Mattie how she always wanted to work off-world. Mattie gently tries to help Gilda relax into bed. Gilda tries earnestly to express to Mattie what she means to her. “I love you. With everything,” she says. “It’s so much it’s the only thing that’s left. I can’t remember half of anything but you’re in all of it.”
Mattie asks Gilda to retell the story of her father – Clark. Gilda remembers that he was annoying at first but eventually he won her over. Her memory slips suddenly and Young Mattie appears again. Gilda tucks Young Mattie into bed and tells her the story of her own mother: “My mother. Was the last tree.” She describes the death of the last tree as Young Mattie falls asleep. Mattie watches her mother also fall asleep. Mattie is left alone.