Cobweb ending explained: What happened to Sarah?

Cobweb spoilers follow.

We knew that Cobweb was never going to have a happy ending as such, but even we weren't expecting the dark revelations in store.

The new horror movie sees eight-year-old Peter become terrified by a tapping sound coming from inside his bedroom wall. His parents Carol and Mark are having none of it and just think that Peter is imagining it all, but it's clear early on that something isn't right with his parents.

They forbid him from going trick-or-treating on Halloween, citing the case of a missing girl years earlier, and when Peter acts out at school by pushing his bully Brian down the stairs, they react by locking him in the basement behind a fridge. Standard.

But the tapping in his wall turns into a voice, and that voice has a terrifying warning for Peter. But before we delve into exactly who (or what) that voice belongs to and the secret his parents are hiding, we need to warn you that major spoilers are ahead.

Let's cut to the chase. That tapping in the wall is coming from Peter's sister Sarah, who was trapped in the walls by Peter's parents before he was born. (It's also implied that they first locked her in the basement, then in a pit, before finishing up on the walls.)

It's never made completely clear why they took such drastic measures, only that something was wrong with Sarah. By the time we see her in the flesh, Sarah can climb walls and has super strength and really sharp teeth — but whether she was born this way or transformed into this monster by her captivity is up to you to decide.

Earlier on in the movie, Mark talks about his pumpkins and how when one turns bad, you've got to rip up the entire patch and start again. It becomes clear that this became an analogy for their parenting, as when Sarah turned out to be a bad egg, they got rid of her and started anew with Peter.

The one time Sarah escaped her captivity, she was seen by a girl on Halloween. Turns out that the girl didn't go missing — Peter's parents killed her and buried her in the back garden to stop her from revealing what was happening to Sarah.

Grim.

Sarah starts to turn Peter against his parents, warning him that they plan to murder her and then imprison him before starting again with a new child. Peter decides to beat them to it by poisoning their soup, which leads to their violent, bloody deaths.

In her dying moments, Carol warns Peter not to let Sarah out — but why would he pay attention to his murderous parents? Peter lets Sarah out and it turns out to be a big mistake. HUGE.

She's obviously been manipulating him this entire time to get him to enact her revenge on their parents. She isn't the biggest Peter fan either and intends to kill him, too. But before that, Sarah's got some other people to kill.

Peter's bully, Brian, turns up at the house with his cousin and two friends to get revenge on him, but Sarah ends up murdering them all instead.

Luckily for Peter, his teacher, Miss Devine, also shows up after receiving a troubling phone call from Peter earlier. Together, they eventually manage to lead Sarah back down to the pit in the basement and trap her in it again.

In a sort-of happy ending, Peter is seen living with Miss Devine, seemingly having avoided any punishment for killing his parents in cold blood.

However, he's haunted by Sarah's final words to him that she'll escape one day, meaning he should be afraid of every creak in the floorboards and every shadow.

So, that's a nice way to have to live your life.

Cobweb is out now in UK cinemas, and is available to buy or rent in the US from Prime Video, iTunes, Vudu and other digital retailers.

Ian Sandwell

Movies Editor, Digital Spy  Ian has more than 10 years of movies journalism experience as a writer and editor.  Starting out as an intern at trade bible Screen International, he was promoted to report and analyse UK box-office results, as well as carving his own niche with horror movies, attending genre festivals around the world.   After moving to Digital Spy, initially as a TV writer, he was nominated for New Digital Talent of the Year at the PPA Digital Awards. He became Movies Editor in 2019, in which role he has interviewed 100s of stars, including Chris Hemsworth, Florence Pugh, Keanu Reeves, Idris Elba and Olivia Colman, become a human encyclopedia for Marvel and appeared as an expert guest on BBC News and on-stage at MCM Comic-Con. Where he can, he continues to push his horror agenda – whether his editor likes it or not.