Prologue

Trapped in a small room on a space ship, a frightened young woman wearing a space suit hears ominous sounds and cries out for help, but no one answers. She then successfully breaks out of the room on her own, and searches for anyone on the ship. Then, she makes her way to the engineering bay, which is drenched and glowing with unknown blue material, and notices what looks like a human being sucked inside the vortex. She screams.

Ceres Station

Ceres, an asteroid in the Belt, has been transformed into the most vital port in the Belt, whose occupants work and live there under harsh circumstances, such as physical deterioration from the gravity and their residence in space, rationing of air and water, and constant mistreatment by Earthers and Martians. Belters have grown contemptuous and have organized activist groups, such as the Outer Planets Alliance (OPA), in order to raise awareness and recognition for the Belters. Joe Miller is a Belter who works as a corrupt detective for Earth-based Star Helix Security, the Earther police force on Ceres, and is often scolded by his own people, who call him a "welwala" (Belter for 'traitor to our people').

Having been assigned a new partner, Dimitri Havelock from Earth, Miller is given a new assignment: to find a missing girl, Julie Mao, a champion pilot and activist who is the daughter of wealthy businessman Jules-Pierre Mao. Miller is ordered to find Julie and bring her back to her family living on Luna. Miller takes a brief detour from his investigation; he tries unsuccessfully to flirt with his ex-lover and former partner, Octavia Muss, who shows signs of discomfort and concern for Miller's well-being. Miller later has a change of heart and decides to end his collaboration with Vargas, the sleazy owner of a sweatshop, whose child workers often develop sickness due to poor air filtration. Miller roughs up Vargas a bit, throwing him into an airlock and removing some of the air, in order to get his point across. He then continues his investigation of Julie afterwards.

Earth

On Earth, politician Chrisjen Avasarala, the U.N. Deputy Undersecretary, is spending time with her husband Arjun and grandson in her Westchester home, when she is contacted by officials and is taken to a U.N. black site, where U.N. officials are interrogating and torturing Heikki Sabong, a Belter member of the OPA accused of carrying contraband stealth technology. However, Sabong refuses to speak and Chrisjen orders to have his interrogation and torture prolonged.

Canterbury

Meanwhile, the Canterbury, a space freighter en route to Ceres Station escorting a shipment of ice, receives a distress signal which most of its crew disregard, considering that any time wasted on anything other than their jobs would result in a late arrival and the loss of their on-time work bonuses. Jim Holden, the executive officer of the Canterbury, is uncomfortable with the majority decision and secretly logs the message with HQ, which means the ship is now obliged to investigate the signal. The Canterbury approaches a damaged ship, known as the Scopuli. Holden is ordered to investigate and takes the Canterbury's shuttle, the Knight, along with some members of the crew: chief engineer Naomi Nagata, mechanic Amos Burton, pilot Alex Kamal, and med-tech officer Shed Garvey. Before the others arrive, Jim admits to Naomi that he was the one who secretly logged the distress call with HQ; she advises him to keep that to himself.

They head to the abandoned Scopuli and search for the source of the distress signal. The crew find a distress transmitter, but no signs of life. Captain McDowell informs the crew that an unidentified ship has entered their vicinity, forcing the crew to evacuate the Scopuli via the Knight. The unidentified ship then fires torpedoes that sail past the Knight and head straight for the Canterbury. Holden's lover, Ade Nygaard, gives one last transmission: "There's something you should know …" before the Canterbury is destroyed - killing everyone on board. Distraught and shaken, Holden and his crew flee.