Warning: SPOILERS ahead for the Black Mirror season 4 episode "Crocodile," as well as for past episodes "Fifteen Million Merits," "White Bear," and "Shut Up and Dance."
While it's never exactly been known for happy endings, Netflix's Black Mirror season 4 has an episode so disturbing that it may shock even die-hard fans. Over the seasons it's been on the air - initially on the U.K.'s Channel 4 and subsequently on Netflix - Black Mirror has gained a reputation for two things: being a really, really good show and also being a really, really bleak one. This was established pretty quickly with early episodes like "Fifteen Million Merits," which featured a character getting pressured into a situation in which she would essentially be raped for the rest of her life.
Perhaps the bleakest episode of Black Mirror prior to season 4 was "White Bear," which revealed that its main character was being tortured as a punishment for having participated in the brutal murder of a child. While that was a harsh revelation, the actual killing wasn't shown, only described. Black Mirror later used horrific acts against children in season 3's "Shut Up and Dance," which saw its main character get blackmailed into criminal activity after a mysterious online hacker caught him looking at photos of children being sexually abused.
In season 4 though, Black Mirror's apparent hatred of children living happy lives is taken a step further, with the episode "Crocodile." The episode centers on Mia (Andrea Riseborough), who commits a murder while staying in a hotel, then sneaks the body out and dumps it at a construction site. Unfortunately, she lives in a world where the memories of witnesses can be recalled via machine and recorded on video. Since the murder she committed happened in the vicinity of a car accident, an insurance investigator (Kiran Sonia Sawar) is sent to get witness recollections, which also place Mia at the scene, and risk exposing her crime.
When the insurance investigator eventually gets around to questioning Mia, she can't stop herself from recalling her murderous memories. The investigator tries to escape, but Mia murders her too, after using the recall device to learn that the investigator's family was aware that she was headed to Mia's house. A crazed Mia then heads to the investigator's house and murders her husband. Unfortunately, their baby sees Mia on the way out of the house, and Mia kills the baby too. The murder isn't shown, but we do see the cops discovering the body afterwards.
While Mia does get her comeuppance in the end, it turns out that she didn't even "need" to kill the baby, as he was born blind, and thus couldn't have been used by the recall machine to place Mia at the house. For a show so full of sad endings, this one really feels like Black Mirror creator Charlie Brooker deliberately twisting the knife into his audience, and perhaps asking them how far they're willing to follow his series into the abyss of despair.
Black Mirror seasons 1-4 are now available to stream on Netflix.