Delving into 10x10's dark reveal and ending (2025)

10x10 ending left viewers shocked back in 2018 when the movie was first released, and it did it again upon its arrival on Netflix UK, where it's now available.

Starring Yellowstone's Kelly Reilly and Luke Evans, this dark thriller is a surprising watch.

The story follows Cathy (Reilly), a woman that's about to open her new business when she is attacked and kidnapped by Robert (Evans). He locks her in a 10x10 room (hence the name) and has a simple request for her: he just wants her name.

But why is Robert interested in Cathy and what does he believe she did? All answers are revealed in the movie's dramatic final act, but if you have any questions left, we're here to help.

So let's dive into 10x10's ending to explain all. Major spoilers ahead for one of Netflix's best thrillers.

10x10 ending explained: Who is Cathy?

Throughout the movie, it appears that Robert knows exactly who Cathy is really and he's just waiting for her to admit who she is. It takes a while, but she finally confesses that she's not really Cathy; her name is actually Natalie and Cathy was the name of her late twin sister.

Her sister died by suicide after their father cheated on their mother and left town. As they were part of a religious community, their father's acts caused the family to be shunned and the shame led to her sister dying.

As a result, Natalie took on her sister's name, Cathy, and dedicated her life to her. (We'll carry on calling her Cathy here as it's easier, but she's really Natalie.)

But what does Cathy have to do with the news reports that Robert watches throughout the movie about the Charleston Three? They were three patients who died in mysterious circumstances, with the nurses put on trial but eventually cleared of any wrongdoing.

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Robert's wife Alana was one of the three patients who died – and it turns out that Cathy was the one who killed her. It appears that one of the ways Cathy decided to dedicate her life to her late sister was to become some sort of avenging angel in her day job as a nurse.

Cathy's patients would admit their darkest secrets to her and, given her religious upbringing and what her father did, Cathy couldn't abide by all these sinners getting away without punishment.

The Charleston Three consisted of John Lamptey, who actually had two wives, Jane Spencer, who lied to the police about her husband beating her up in order to get more divorce money, and Robert's wife Alana, who was cheating on Robert without him knowing.

"See, the Bible says that we should hold marriage with honour. Your wife was a sinner. Your wife was a whore. She was a sinner. So you tell me, who's in the wrong? You? Natalie? Or your wife? I did it. I killed her," Cathy tells Robert.

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He doesn't believe her, especially when she suggests that his daughter Summer isn't actually his. Cathy manages to escape from the room and, in unfortunate timing, Summer has just come back home with the nanny. Cathy takes Summer hostage, but Summer bites Cathy and escapes.

As Robert prepares to leave and take the recordings of Cathy's confessions to the police, Cathy attacks him in the garage. He knocks her unconscious and as she falls, she unwittingly knocks the latch on the garage door, which then slams down on her.

It's not clear if she's dead or just in a very bad way, but Robert and his daughter are now safe. In the final moments of 10x10, Robert tells his daughter that he loves her and that she's his child.

Awww.

10x10 is available to watch now on Netflix UK.