Her husband Aiden suggests that she visit a doctor, Dr. Webber, for breast cancer screening.

During a Rorschach test, Ella hallucinates a very tall woman, a family of dead bugs, and a grandfather clock.

Dr. Simmons suggests that the clock represents Ella's fear of ending her family line and that she's ready for the next step in the treatment.

In a sensory deprivation chamber designed to make her face her fears, Ella sees herself with a baby swinging from between her legs like a pendulum, as well as terrifying scenes of childbirth.

When the chamber opens, she sees the tall woman standing at her tank, runs, but slips and hits her head.

When Ella awakes, Dr. Simmons tells her that a strong reaction to the treatment is a good sign.

Ella hallucinates a spider again and attempts to smash Shauna's belly with a heavy book, but Aiden stops her.

The side effects continue; Ella loses her colour vision, hears the ticking of a grandfather clock, and sees normal people as the tall woman.

Aiden admits he met Dr. Simmons at a trade show and plotted to have Dr. Webber suggest the study to Ella.

The website's consensus reads: "While Clock may strain some viewers' suspension of disbelief, it's a mostly effective attempt to view reproductive pressures through a chilling horror lens.

[11] James Croot of Stuff called Clock one of the most "disturbing, thought-provoking horrors conceived in a long time," complimented the film's approach on human nature, and praised the performance of Dianna Agron.

[12] Haleigh Foutch of Collider included Clock in their "Best Horror Movies on Hulu Right Now" list, describing it as a "meditation on the pressures women face around reproduction," saying, "The film has a lot to say about its themes and perfectly uses the thriller medium to manifest and physicalize the internal struggles that aging women deal with on a daily basis.

"[13] Mary Beth McAndrews of Dread Central gave the film a grade of 3 out of 5 stars, writing, "Despite some third-act stumbles, Clock is a shocking experience supported by stunning performances from Dianna Agron and Melora Hardin.