As another day of fantasy plays out in Westworld — a vast, remote park where guests pay top dollar to share wild-west adventures with android "hosts" — top programmer Bernard Lowe alerts park founder Dr. Robert Ford about incidents of aberrant behavior cropping up in some recently re-coded hosts. Meanwhile, in the Westworld town of Sweetwater, a rancher’s daughter named Dolores encounters a gunslinger named Teddy in the street — but their predictable narrative is upended by the appearance of a ruthless Man in Black and, later, by a supporting host’s unscripted encounter with an artifact of the outside world.

A pair of guests, first-timer William and repeat visitor Logan, arrive at Westworld with different expectations and agendas. Bernard and Quality Assurance head Theresa Cullen debate whether a recent host anomaly is contagious. Meanwhile, behavior engineer Elsie Hughes tweaks the emotions of Maeve, a madam in Sweetwater's brothel, in order to avoid a recall. Cocky programmer Lee Sizemore pitches his latest narrative to the team, but Dr. Ford has other ideas. The Man in Black conscripts a condemned man, Lawrence, to help him uncover Westworld's deepest secrets.

Elsie and her colleague Ashley Stubbs head into the hills in pursuit of a missing host. Teddy gets a new backstory, which sets him off in pursuit of a new villain, leaving Dolores alone in Sweetwater. Bernard investigates the origins of madness and hallucinations within the hosts. William finds an attraction he'd like to pursue and drags Logan along for the ride.