| No. | Title | Directed by | Written by | Original release date |
| 1 | "Countdown" | Derek Tsang | David Benioff & D. B. Weiss & Alexander Woo | March 21, 2024 (2024-03-21) |
| In 1960s China during the Cultural Revolution, Ye Wenjie witnesses her father being beaten to death in a struggle session. After she is discovered to be in possession of a copy of Silent Spring, which was banned, Ye is transferred to a remote military base with a large radio telescope dish intended for interstellar communications. In present day UK, Oxford physicist Vera Ye (the daughter of Ye Wenjie) dies by suicide. A group of Vera's former physics students — Auggie Salazar, Jack Rooney, Jin Cheng, Saul Durand, and Will Downing — discuss how recent science experiments have stopped making sense. Clarence "Da" Shi, a British detective working for the Strategic Intelligence Agency, comes across multiple suicides by scientists, several of whom possessed an impossibly advanced virtual reality (VR) gaming headset. Ye Wenjie offers Vera's VR headset to physicist Jin. Auggie, a materials scientist, starts seeing a countdown timer – visible only to her – floating in her line of vision. An unknown woman (later revealed as Tatiana) tells Auggie to abandon her breakthrough nanofiber research if she wants the countdown to disappear. The woman also tells Auggie to watch the sky at midnight. The night sky ends up flashing a pattern that matches Auggie's countdown timer, violating all known laws of physics. |
| 2 | "Red Coast" | Derek Tsang | Rose Cartwright | March 21, 2024 (2024-03-21) |
| After successfully demonstrating her nanofiber technology, Auggie orders the research to be halted, after which the countdown timer disappears from her vision. Using the VR headset from Ye, Jin advances through the 3 Body video game. She shows the headset to Jack, only for the interface to swiftly reject him. Later, a similar headset is delivered to his home with an invitation to play the game. Will confides in Jack that he is dying of pancreatic cancer. In 1970s China, Ye Wenjie continues her work at the SETI site and realizes that the sun can amplify radio signals. However, a colleague claims ownership of her proposal to exploit that possibility, and she is chastised for not rejecting it due to the symbolism of Mao Zedong being China's "Red Sun". Ye spitefully, and clandestinely, implements the plan regardless, broadcasting a message to the universe. She later meets Mike Evans, a radical environmentalist, and receives a radio response from a pacifist alien warning her not to make contact again, as the other aliens on that planet would be eager to invade Earth. Disillusioned with the world, Ye replies anyway, saying humanity can no longer save itself and that she will help the aliens gain control of Earth. |
| 3 | "Destroyer of Worlds" | Andrew Stanton | Alexander Woo | March 21, 2024 (2024-03-21) |
| In the present, Auggie discovers Jack's gaming headset and tries it on, only to be violently ejected. Distraught, she demands Jin and Jack stop playing, but they press on. When Auggie powers up her nanofiber project, the countdown returns and she again hastily shuts the project down. Within the game, Jin and Jack collaborate and complete levels 2 and 3. It is revealed the headset is actually a recruitment tool used by Mike Evans, who is now a wealthy oil tycoon and has been communicating regularly with the aliens. Level 4 takes place in the real world; Jack and Jin meet Tatiana, who does not appear on any surveillance cameras. In the game, they are shown the alien civilization's evolution in a star system containing a three body problem four light years away and their subsequent departure for Earth. Jack rejects this narrative and asks to leave. He is allowed to but is later murdered at his house by Tatiana. Neither Clarence, who's staking out Jack's house, nor any of the 18 interior security cameras can sense Tatiana's presence. |
| 4 | "Our Lord" | Minkie Spiro | Madhuri Shekar | March 21, 2024 (2024-03-21) |
| In 1984, somewhere in the North Atlantic, Evans takes Ye Wenjie to his ship, Judgment Day, a vessel from which they can use advanced satellite technology to communicate with the aliens, who are called San-Ti (Trisolarans). In 2024, following Jack's murder, Thomas Wade (Clarence's superior) and Clarence enlist Jin's help in infiltrating Evans' secret organization to collect intelligence. Under Wade and Clarence's guidance, Jin attends a secret countryside meeting where Ye Wenjie reveals herself to be its leader and that the purpose of the Earth-Trisolaris movement is to help the San-Ti arrive and take over the Earth. British security forces raid the meeting. After realizing Jin is a spy, Tatiana attempts to assassinate her, sparking a shootout. Tatiana escapes but Ye Wenjie and most of the cultists are captured or shot. Meanwhile, Evans tells the story of Little Red Riding Hood and the Big Bad Wolf to a San-Ti liaison. However, the San-Ti struggle to understand the concept of fiction. The liaison chillingly interprets the story as a testament to human deception and claims they cannot coexist with humanity. |
| 5 | "Judgment Day" | Minkie Spiro | David Benioff & D. B. Weiss | March 21, 2024 (2024-03-21) |
| Clarence interrogates Ye Wenjie, who claims the San-Ti allowed her to be captured because she is no longer needed. Evans' ship, Judgment Day, is scheduled to go through the Panama Canal. Wade enlists Auggie and a Royal Navy team — headed by Raj, Jin's boyfriend — to obtain the data onboard. Auggie's nanofibers are used to horizontally slice through the ship, killing everyone aboard. Wade's team locates the data disk and tries to decrypt it, which the San-Ti allow. Wade plays Ye Wenjie the recording of the San-Ti's confusion over humanity's ability to lie. Jin and Wade open a file in the data disk using the VR headsets. The San-Ti avatar are using a pair of Sophons – each a single proton, unfolded in a high-dimension to massive size, forming a sentient supercomputer – to cause the anomalous effects observed in particle accelerators and in people's vision, while allowing instantaneous communication with their fleet. The avatar details how crippling Earth's scientific advancement will prevent humans from technologically surpassing them before they arrive. A Sophon expands to envelop the planet, while displaying the message "YOU ARE BUGS" on all electronic displays on Earth, revealing the existence and power of the San-Ti. |
| 6 | "The Stars Our Destination" | Minkie Spiro | Alexander Woo | March 21, 2024 (2024-03-21) |
| The "Eye in the Sky" incident causes worldwide panic. Wade and the PDC (Planetary Defense Council) gather a group of experts to discuss how to intercept the San-Ti fleet. It is established that if a probe were to reach at least 1% light speed, it would intercept the incoming ships in 200 years, giving Earth 200 years' advance knowledge. Jin proposes the Staircase Project, using a thousand nuclear bombs as propulsion sources for a probe with radiation sails. Based on Raj's performance in Panama, he is granted permission to join the PDC. Auggie, repulsed by the deadly use of her nanofibers against Judgment Day, becomes depressed and reluctant to further assist the PDC. Clarence asks Ye Wenjie why Vera Ye committed suicide, to which she responds that Vera discovered her mother's dealings with the San-Ti through Ye Wenjie's correspondence with Evans. Clarence releases Ye Wenjie and assigns an officer to keep track of her whereabouts. Due to his illness and medication, Will hallucinates and reflects on his unrequited love towards Jin. As a result, he visits The Stars Our Destination Foundation to purchase the star DX3906 for her. |
| 7 | "Only Advance" | Jeremy Podeswa | David Benioff & D. B. Weiss | March 21, 2024 (2024-03-21) |
| The ownership certificate of star DX3906 is sent anonymously to Jin. Wade demonstrates cryogenic technology to PDC members, reviving a chimpanzee who had been in cryo-sleep. He plans to enter cryo-sleep himself to be present when the San-Ti arrive in 400 years, stating that humanity can "Only advance." Due to insufficient nuclear bombs for use as propulsion, the maximum payload of the interstellar probe will only be enough to hold a human brain. Auggie makes her nanofiber research public and leaves the country. Given Will's imminent death from cancer, Wade suggests he fill the candidacy as the brain in the Staircase Project. Ye Wenjie meets with Saul and attempts to pass on her knowledge about cosmic sociology in the form of a joke that the San-Ti will have difficulty deciphering, saying, "Don't play with God." Will consents to the Staircase Project and euthanizes himself with Saul at his side. Jin, discovering DX3906 was a gift from Will, rushes to the hospital only to find his brain has already been extracted. Ye Wenjie flies back to China and visits the Red Coast dish site, intent on committing suicide, but is stopped by Tatiana, who offers to kill her peacefully on orders from the San-Ti. The two watch one final sunset together. |
| 8 | "Wallfacer" | Jeremy Podeswa | David Benioff & D. B. Weiss | March 21, 2024 (2024-03-21) |
| After a one-night stand, Saul's lover is hit by an errant car and dies in front of him. Clarence's investigation reveals that it was a San-Ti assassination attempt, with Saul as the intended victim. Saul is taken into protective custody and flown to the United Nations, where the Wallfacer Project is announced. Saul is selected as one of three Wallfacers who are each tasked to develop a plan to defeat the San-Ti contained entirely within their own minds, as the San-Ti are unable to read minds. Saul tries to reject his position and leaves the UN, only to be shot by a sniper. He survives thanks to his bulletproof clothing and reconsiders why the San-Ti want him dead. Wade and Jin oversee the Staircase Project, where Will's cryogenically frozen brain is launched into space, in hope that the San-Ti will intercept and reconstruct his body with it. Shortly after the detonation sequence starts, the sail malfunctions and sends the probe off course. The San-Ti liaison taunts Wade for his failure. Clarence takes a despondent Jin and similarly depressive Saul to see a swarm of cicadas, insects that have survived despite humanity's decades-long attempts to eradicate them, implying humanity has the same resilience. |
