In San Francisco, journalist Eddie Brock (Tom Hardy) interviews serial killer Cletus Kasady (Woody Harrelson). Brock’s girlfriend, lawyer Ann Weying (Michelle Williams), works for the Life Foundation. Its CEO, Carlton Drake (Riz Ahmed), retrieves a space probe containing symbiotes and attempts to merge them with disabled vagrants, leading to their deaths and attracting Brock’s attention.

Aided by Dr. Dora Skirth (Jenny Slate), Brock breaks into the Life Foundation’s headquarters and is attacked by one of Drake’s subjects, Donna Diego (Michelle Lee), who has been driven insane by her symbiote, Scream. Brock merges with another symbiote, Venom, who helps him escape. Scream escapes, and another symbiote, Riot, infects Dr. Emerson Collins (Reid Scott).

Brock is ambushed by mercenaries led by Drake’s enforcer Roland Treece (Scott Haze) at his apartment, but fends them off with Venom’s help. Venom reveals that the symbiotes want to kill him for wanting to experience what his hosts experience rather than consume them, and makes a deal with Brock to use Brock as a host to regain his strength in exchange for Brock using Venom’s powers to help people. Scream locates them and attempts to kill Venom, but Venom manages to kill her before Brock is captured by the Life Foundation.

Drake kills Skirth, tortures Brock, and plans to launch another probe to bring more symbiotes to Earth. Riot possesses Drake and begins slaughtering Drake’s personnel to find Venom. Ann arrives and frees Brock, who orders her to proceed with the launch. Venom lures Riot to the launch platform, where the loud noisess weaken Riot, allowing Venom to impale him onto the probe as it takes off.

Ann exposes the Life Foundation, leading to Treece and his men being arrested, and becomes fascinated by the symbiotes, while Brock and Venom escape and go on as the city’s "Lethal Protector".

In a mid-credits scene, the probe is drifting through space when it is swarmed by hundreds of symbiotes.

In an after-credits scene, Treece arrives in prison and is confronted by Kasady, who wants his own symbiote.

Tom Holland doesn’t appear and there are no references to Spider-Man.

PG-13 aside from Venom slashing through Treece’s men to escape.

Venom forces Brock to dance in public to assert his dominance over him.