The Chalk Line has become a major hit on Netflix as viewers marvel at the change in the fortunes of a young girl named Clara. Paula and Simon, a wealthy couple struggling to conceive, stumble upon a disheveled Clara on the street and take her in. 

Clara becomes the glue that holds the couple’s crumbling marriage together – they see her as their opportunity to raise a child. However, they notice that Clara is deeply troubled and perhaps haunted. She’s terrified of a bogeyman who’ll catch her if she moves beyond a chalk square she draws on the ground. 

The Chalk Line is loosely based on the kidnapping, torture, and sexual abuse of Elisabeth Fritzl

Paula and Simon connect Clara to Ingrid, a girl who went missing when she was 12. The film reveals that Eduardo, the couple’s neighbor, is a pedophile and murderer who killed Ingrid after imprisoning and repeatedly raping her in his basement. Ingrid gave birth to Carla following sexual abuse by Eduardo. 

He is the bogeyman that Clara so intensely fears. The film shows that Eduardo’s wife knows about his crimes, making her complicit in the kidnappings of Ingrid and Clara. Thankfully, the evil couple are arrested at the end of the film. Clara ends up happy with her grandmother in Germany, and Paula finally gets pregnant. 

The filmmakers based the film’s narrative on the sad story of Elisabeth Fritzl, who was held captive by her Austrian father, Josef Fritzl, for nearly 25 years. Elisabeth’s captivity started in August 1984 after Josef asked her to help him install her prison door. 

Elisabeth had run away from home several times, so Josef explained her disappearance by saying she’d fled to join a sect. Unbeknownst to anyone else, Elisabeth became Josef’s sex slave. 

He kept her in inhumane conditions ranging from extremely hot in the summer to paralyzingly cold in the winter. Josef reportedly raped Elisabeth at least 3,000 times, resulting in seven babies, one of whom passed away hours after birth. 

Josef raised three of the kids alongside his wife, Rosemarie. He made it seem like Elisabeth had sent the babies from her sect to be brought up by their grandparents. Fritzl made Elisabeth write letters saying she was okay but couldn’t look after the kids. 

The remaining three remained underground with Elisabeth, never to see the light until her rescue. Fritzl threatened Elisabeth and her kids with death if they tried to escape. His indictment read:

“He told them he had installed a system so that the doors would give them electric shocks if they tried to open them and that poison would be released into the cellar if they tried to escape, killing them all instantly.”

Elisabeth escaped after Josef rushed her eldest child to the hospital. She pleaded with Josef to allow her to visit the hospital; Josef, a man who rarely showed mercy, relented. He told authorities that Elisabeth had mysteriously appeared on his doorstep. 

Authorities swiftly arrested Elisabeth, ready to charge her with child neglect. Elisabeth said she had a wildly different story that she would only tell if they promised she would never see Josef again.