When it comes to films that linger in your thoughts long after the credits fade, “Eden Lake” undoubtedly deserves a mention. The film follows a couple, Steve (Fassbender) and Jenny (Reilly), as they seek relaxation at Eden Lake, only to find themselves menaced by a gang of delinquent teens led by the menacing Brett (Jack O’Connell). Tensions mount when Steve fights back, spiraling into a sequence of increasingly terrifying events. Contrary to typical narratives, Steve and Jenny do not enjoy a fairy tale ending.

Helmed by English filmmaker James Watkins, known for his work on “Black Mirror” and “Speak No Evil,” “Eden Lake” has left a lasting impression on both critics and audiences. On Rotten Tomatoes, it boasts a 76% rating on the Tomatometer and a 65% audience score, with viewers acknowledging the film’s ability to deeply disturb. Its chilling conclusion continues to provoke strong reactions.

The finale of “Eden Lake” is polarizing, challenging the traditional horror trope of villains receiving their comeuppance. Instead, the film opts for a shocking and divisive twist that leaves viewers questioning the fate of the characters played by Reilly and Fassbender. This departure from the expected generates debate and keeps audiences engaged, pondering whether the protagonists truly deserved their grim outcomes.

The authentic chemistry between Reilly and Fassbender in “Eden Lake” may have roots in their past collaboration. The two had previously worked together in a 1999 theater production of Anton Chekhov’s “Three Sisters,” with Fassbender as Fedotik and Reilly as Irina. Little could they have imagined that, less than a decade later, they would reunite in such a visceral and haunting film.

Reilly understood this as well, telling Daily Dead in 2021 that she anticipated the ending becoming a major talking point about the film. “I remember shooting the ending of ‘Eden Lake’ and saying to the director, ‘You know people are going to hate this ending. They are going to absolutely hate this,’” she said. “But I loved the ending. I loved that she didn’t get out because that made the horror feel all the more real. It was very disturbing. I really loved making that film.”

If the chemistry between Fassbender and Reilly seemed believable and as if they had known each other for a while, that’s because they had. The pair appeared in the 1999 theater production of Anton Chekhov’s “Three Sisters,” in which Fassbender played Fedotik, and Reilly portrayed Irina. At the time, it’s unlikely they could have anticipated starring in such a gory and disturbing film like “Eden Lake” less than a decade later.