In The Flesh is a zombie show about what happens after they develop a cure for zombism and reintegrate them back into society. Unlike most modern zombie settings, "Partially Deceased Syndrome Sufferers" are your classic "crawling out of the grave" type of undead that aren't capable of spreading it through bites. Instead, if they eat a person, that person just dies. On top of this, scientists only know how to treat it through an injectable medicine, but many physical effects of dying are permanent and they are capable of reverting back if they go off of their meds or take a drug called Blue Oblivion. Underneath their makeup and contacts, they still look like corpses and have some degree of decay. This leads people to be very cautious around PDS sufferers because they're unsure if they're taking the meds properly or worse- not absorbing them. There is a local militia called the HVF who used to actively fight the undead who are now adjusting to both civilian life and also the fact that the enemy is now considered human. They don't get much action anymore with the exception of catching the few untreated undead that still roam around in the wilderness and bringing them in for the reward, though this is a step up from their original stance of killing any they find included treated ones.
The show follows Kieren Walker as he returns to his family after years of being dead from a suicide at 18. His younger sister, Jem, was a member of the HVF and found him and another zombie eating her girlfriend, Lisa. Jem couldn't bring herself to kill either of them, and this led to them both being able to be treated. However, she struggles with the guilt that she could have done something to stop him from killing Lisa and is initially hostile towards him when he returns home. To complicate things, his old "hunting buddy" finds Kieren and introduces herself as Amy Dyer. She's an outspoken hippie who tries to seem like she doesn't care about what people think and believes people should get used to the situation. She also doesn't cover herself up with the makeup and contacts, while Kieren can't stand to look at himself without them. She's wild enough to push him outside his comfort zone so he can get comfortable with socializing with people again, and she becomes his best friend. His BDFF, (Best Dead Friend Forever) as she calls it.
There is a group called the Undead Liberation Army who are first introduced to Kieren by his roommate while he was still in the treatment facility. They live on a commune like peaceful hippies, but are extremist in their beliefs and want to cause the Second Rising to get revenge on the living. They are also creators of Blue Oblivion, the drug that can temporarily revert the user back into a predatory state before it wears off. They use it to coordinate terrorist attacks on the living, and his old roommate in the facility took the drug to attack the staff.
On the polar opposite side to the Undead Liberation Army, there is a political party called Victus who was formed in opposition to reintegrating the undead back into society. They gain political control over the town, and push an already hostile environment even further.