We're back in the world of Season 2 as attractive young people lounge about poolside, seemingly not giving a damn about the zombie apocalypse. A lovely lady delivers a phone to a table and an elderly-looking hand picks it up, making a call to a well-dressed bald fella known only as The Man. The Man's got a metal container full of hooded prisoners, which are the people on his notorious 'List,' and there's one name yet to be scratched off: Dr. Harold Teller.
Dr. Teller is holed up at Mercy Labs, which is now an isolated compound where a handful of survivors make their home. They won't give up Teller to The Man, so The Man takes a near-feral child he refers to as Nature Boy hostage and says he'll be back in 24 hours, when Dr. Teller better reveal himself.
Nature Boy comes to and escapes from The Man's vehicle when he sees there's a live zombie in the trunk with him. The kid runs through the wilderness and literally bumps right into 10K, who's taking care of a horde of zombies with Roberta, Addy, Doc and Cassandra, who's in her half-Z state. Murphy's there, too, cradling Lucy, his zombaby.
After a brief run-in with Nature Boy's sister, Red, the gang returns the siblings to the compound. Soon, they're recruited by Dr. Harold Teller to help defend the place against The Man and his armed minions. Rumor hath it that The Man is some sort of avenging angel, punishing the scientists that are somewhat connected to the outbreak of the zombie virus; as he was allegedly only working on fungus-based painkillers, Dr. Teller doesn't understand why he would be on The Man's list.
The true nature of Teller's work is revealed when Murphy starts hearing whispering voices. He follows them to Teller's lab, where he finds two grotesquely deformed people locked in a room, begging to be given mercy. The discovery becomes even more disturbing when it's revealed that one of them is Dr. Teller's wife, Sarah.
Y'see, Teller and his wife were working on a fungus-based cure for the Z virus. When zombies attacked the lab, the 'cure' became airborne, protecting those contaminated from becoming Z but turning them into horrible fungus monsters instead. Murphy is deeply shaken by this and wants to leave, but Roberta convinces the team to stay and help defend the place against The Man.
Meanwhile, 10K has been bonding with Red and Nature Boy, whom Doc refers to as '5K' after the kid starts dressing like his new hero (jet-black hair and all). 5K was raised by crows (seriously), so he's definitely got survival instincts; he's now also pretty good with a slingshot, thanks to 10K's lessons.
As the sun sets on this very strange day, Roberta does a recon around the perimeter and catches sight of The Man. It ends up being a zombie decoy and Roberta is knocked unconscious by The Man and his troops. She's now being held amongst the hooded prisoners, though the gang back at the lab decides to stick with what Doc refers to as 'Plan A.'
So what is Plan A? It involves a lot of red paint, as the walls of the compound and large metal sheets have all been given a fresh coat, turning the lab into a rather intimidating-looking fortress. Everyone's dressed for battle in their red hazmat suits, too, basking in a color scheme that brings to mind violence, blood and heat. Is it enough to rattle The Man? He's brought his own red item: Roberta's bandana, and he wants to swap her for Dr. Teller.
Doc needs proof of life, and gets more than that when Roberta gets on the walkie talkie, now free from the metal shed thanks to 5K knocking out the guard with his slingshot. The Man counters by unleashing a horde of zombies, which allows everyone to show off the shooting skills they learned from Roberta as she, 10K, Red and 5K circle back in to help bring the red heat.
The Man then unleashes his ace in the hole: a squad of zombies that have been 'mercy-proofed' thanks to their makeshift metal helmets. Can't get a head shot! These berserker Z's are too much for the gang and they fall back to the lab, where Sarah and her fellow fungus monsters show off their own battle skills as they take out The Man's goons. Unfortunately, Sarah is badly wounded, prompting Dr. Teller to finally give his wife mercy.
Just then, the wall explodes, and The Man emerges from the rubble, dressed in a makeshift hazmat suit (saran wrap and duct tape) and helmet. He knocks out Dr. Teller and carries him out as Murphy looks on in awe.
The gang takes care of the remaining mercy-proofed zombies via some cleverly choreographed gunplay (and at least one ferocious Z-whacker performance by Addy) and make it out of the lab. They look up to see a helicopter transporting The Man's metal container of prisoners, en route to some unknown destination. Red is heartbroken when 10K reports that 5K is nowhere to be found and ends up rushing a horde of oncoming zombies in mad fury.
The metal container is delivered to the fancy house we saw at the beginning of the episode. The prisoners are escorted poolside, where their hoods are removed and they face their unknown host. Could this be the fabled Zona we've heard so much about?
The episode ends with the slain 5K, being watched over and mourned by his murder of crows. A fine warrior, and an even finer young man!