High Tension
High Tension (French: Haute tension, ; also known as Switchblade Romance in some English-speaking countries) is a 2003 French slasher film directed by Alexandre Aja, co-written with Grégory Levasseur, and starring Cécile de France and Maïwenn. The plot focuses on a young student who travels with her classmate to visit her family at their secluded farmhouse, where a murderer breaks in on the night of their arrival.
Plot
Best friends Marie and Alex are on their way to stay at Alex's parents' house for the weekend to study. Upon arriving, Alex gives Marie a tour of her house, then they have dinner and go to bed. While the family sleeps, Marie stays awake in the guest bedroom, listening to music and masturbating. Marie hears a doorbell ring and Alex's father Daniel answers it. The man slashes Daniel's face with a straight razor, presses his head between two staircase spindles, and shoves a bookcase towards his head, decapitating him. Alex's mother, awakened by the noise, finds Daniel dead and is approached by the killer.