The Chalk Line

Paula and her husband Simón lead a pleasant life in their affluent neighborhood. One fateful night, they come across a mute young girl wandering alone in the street and take her to the hospital, seeking to ensure her safety.

At the hospital, Paula and Simón learn that the facility cannot trace Clara's family. They decide to temporarily foster her, using the name Clara as a clue in their attempts to help her recover.

As Clara moves in with Paula and Simón, they create safe spaces for her by drawing chalk lines throughout the house. This gesture is intended to provide comfort and security to Clara as she settles into her new environment.

During a visit from her doctor Gloria, Clara is encouraged to go outside. However, this leads her to react distressingly and expresses her discomfort by exclaiming 'buma', showcasing her deep-seated fears.

Paula hosts her friend Claudia for breakfast, hoping a playdate will help bond Clara and Paula’s daughter. Unfortunately, a disastrous incident occurs when Claudia accidentally consumes a shard of glass, leading to panic and a need for medical assistance.

In the aftermath of the breakfast incident, Paula conceals it from Gloria at Simón's urging. Meanwhile, Paula grows increasingly suspicious when she overhears Clara saying the German word for chalk, leading her to believe Clara may have ties to Germany.

After deciphering Clara's repeated term 'buma', Paula discovers it means 'Buhmann' in German, alluding to a bogeyman. This revelation forces Paula to confront the potential dangers surrounding Clara and herself.

Once Paula chokes on a shard of glass and rushes to the bathroom, she marks her territory with a chalk line. Returning in distress, she discovers Clara has vanished without a trace, leading to a frantic search.

In despair over Clara's disappearance, Simón and friends conduct an intervention to console Paula. However, Paula dismisses their concerns, insisting her connection with Clara is vital, despite Simón’s worries about her mental well-being.

Alone and distraught, Paula receives a shocking phone call from Clara, which sends her into a panic. When she contacts the police, they inform her that the call originated from her own cellphone, leading to further complications.

Determined to uncover the truth, Paula steals documents related to Clara's case. She is horrified to find a story about Ingrid, a Swiss girl who was found deceased, sparking her fears about Clara’s fate.

Upon examining one of Clara's drawings, Paula begins to suspect Eduardo, her neighbor, of being connected to Clara's disappearance. Flashbacks reveal Eduardo’s ominous behavior towards Clara, raising the tension.

At a dinner gathering, Paula confronts Eduardo about Clara's situation and his past involvement with Ingrid. Tensions escalate when Eduardo attempts to abduct Clara, revealing his sinister intentions.

In a desperate move, Paula distracts Eduardo long enough for Clara to escape and seek help. Paula throws a piece of chalk for Clara to hide behind, illustrating her cleverness and resourcefulness in the face of danger.

After a police raid on Eduardo's house, Clara and Paula finally reconnect through a heartfelt video call. Clara joyously reunites with her grandmother, while Paula and Simón make plans to start anew, moving on from their traumatic experience.