Gretel's boyfriend Ashton introduces her to a strain of marijuana called Black Forest produced by an old lady named Agnes in Pasadena. When Gretel urges him to bring more, Ashton visits Agnes and is drugged, realizing too late that Agnes is a witch who feeds on the flesh of men to steal their youth. She then devours parts of Ashton's body and, in a final twist, drains his life force to restore her own youth.
[Gretel] and her brother Hansel set out to find Ashton, but the search is met with mockery from the police, and their trail dissolves as Agnes remains inscrutable and silent about the truth behind the disappearances.
Meanwhile, trouble brews with a local drug kingpin, Carlos. He bullies Agnes’ dealer, Manny, into revealing the address of her secluded house. Manny tries to warn her but is killed by Agnes, and Carlos soon arrives only to be dispatched by Agnes herself, who recasts him as a zombie after a brutal confrontation.
The next morning, Gretel teams up with Manny’s girlfriend, Bianca, to infiltrate Agnes’ home. Before they depart, Gretel sends an email to [Hansel] letting him know she plans to confront Agnes again. Bianca helps by creating distractions as Gretel makes her move.
Inside the basement, Gretel uncovers the eerie Black Forest crop and the grisly remains of the men Agnes has killed. She leaves a bright trail of Skittles to help her navigate the labyrinthine plants, an eerie breadcrumb path through the horror she’s uncovered. Agnes eventually recognizes the ruse, and Gretel and Bianca are captured.
[Hansel] arrives to help just as the situation escalates, confronting Carlos and fighting off the zombified foe. Though Hansel defeats Carlos, he is knocked unconscious by Agnes and imprisoned in the oven room, a chilling setup for a grim outcome.
Gretel and Bianca manage to break free from their restraints and rush to stop Agnes just as she is about to prepare Hansel. Bianca is sadly killed in the struggle, leaving Gretel to press onward.
In a desperate confrontation, Gretel shoves Agnes into the oven and locks the door. The oven explodes, triggering a catastrophic fire that consumes the marijuana crop and the house. Hansel and Gretel escape the blazing ruin as first responders arrive on the scene.
One rescuer stoops to inspect a cat wandering through the ashes and retrieves it, only to be confronted with a sudden, brutal interruption that ends in tragedy. The danger doesn’t end there, as Agnes resurfaces behind the wheel, driving away from the scene and into an uncertain future.
