The terrifying and depressing new BBC series In the Flesh delivers an original take on the often-tired zombie metaphor. In this post-apocalyptic tale, the world fell prey to a zombie plague — until scientists figured out a medication that rehabilitates many who suffer from "partial death syndrome." The problem? Humans aren't ready to welcome these former brain-eating monsters back into their communities.

Spoilers ahead.

The series focuses on one rehabilitated zombie, Kieran, a sensitive young man who rose from the dead after committing suicide over the death of his best friend. He's wracked with guilt over what he did as a zombie, and suffers traumatic flashbacks to murdering a young woman. His conflicted feelings are only compounded when he discovers that his small town was ground zero of the HVF, or human volunteer force, which rose up to fight the zombies when the government's resources fell short. And his beloved sister, Jem, was one of the most ardent HVF fighters. Though his parents welcome him back home — as long as he receives his daily spinal injection to keep his brain de-zombified — his sister has issues.

Meanwhile, the town's church leaders are hellbent on eradicating any "partly dead" in their midst. And they have powerful allies in the HVF, which has officially been disbanded but continues in semi-secret. Meanwhile, one of Kieran's friends from the PDS rehab facility has told him about an underground undead preacher, who wants the zombies to revolt against their human oppressors.

There's an interesting turnabout in this zombie tale, where the once-deadly monsters are now the victims of humans. Kieran and his family watch in horror as a nice old lady across the street is murdered by the HVF — just for being an ex-zombie. Though it's technically illegal to murder zombies, nobody is willing to enforce the laws out in the country. So Kieran has to face the demons in his blood-soaked memories, as well as the bloodthirsty townsfolk who were once his friends.

I think what's most interesting about the series is the way it serves as a metaphor for what happens to people who are mentally ill when they try to return to their old lives after a breakdown. There are shades of Silver Linings Playbook here, with Kieran taking his awful meds and struggling to feel normal. But it's also about the rehabilitation of violent criminals. Should a guy who ate an innocent woman's brain really be allowed to roam free, even if he's heavily medicated and "cured" of his syndrome? After all, the HVF aren't like the KKK — they were defending the town from actual danger, not racist phantoms. They had to kill to survive. And there are no guarantees that the zombie "cure" will work in the long term.

In the Flesh has set up a riveting monster story that poses some disturbing ethical questions. Check it out on BBC Three in the UK.