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Z Nation Wiki
Return to Mercy Labs
Season 4, Episode 11
Return to Mercy Labs.jpeg
Air date December 8, 2017
Written by Jodi Binstock
Directed by Jodi Binstock
U.S. Viewers 0.57 millions
Episode Guide
"Mt. Weather"

"Return to Mercy Labs" is the eleventh episode of Season 4 of Z Nation and the fifty-third episode of the series overall. It was aired in the United States on December 8, 2017 at 8/7c .

Plot Synopsis[]

The team has made a habit of following Roberta Warren for a long time now. While it’s gotten them into all kinds of adventures, even she isn’t sure where she’s heading now. As they head out of Chicago and end up walking across Illinois, the good people of Operation Bitemark finally make it to a place they’ve been before: a factory outside of Springfield, Illinois. This is the same place where an epic battle went down with The Man for possession Dr. Harold Teller.

It's hardest for 10K , because this is where he met Red and where he taught 5K to use a slingshot. Doc tries to make him feel better, but 10K continues on as his stoic self into the laboratory, following Roberta. When they ask her what’s inside, she replies that she hopes she finds out. Either way, she’s following her hunch deep into the factory. She knows that whatever is here, it's going to tell her whatever this Black Rainbow plan is and hopefully how to stop it. Roberta is desperate for answers, and her dreams are still leading her and the team down some long roads.

This lab has bad memories. It was where Murphy was able to hear Dr. Tellers wife because of his half-zombie state. She, and several others, were partial zombies. Dr. Teller's zombie wife, in particular, was asking about their son, and it turns out that now that they’re here, they’ve discovered that Dr. Teller sealed their son Andrew in a glass box on life support. Murphy says he understands: he'd give anything to keep Lucy frozen in time.

Meanwhile, Roberta and 10K go off in search of whatever Roberta’s dreams are telling her. As long as she follows the dream, she is able to find her way through the lab and seek out the canisters she needs. Finally, when the dream starts to fail her, she asks 10K to punch her, because that’s what often triggers the vision. It’s hard to do, but ultimately it helps, and she ends up with another gas canisters.

Meanwhile, up at the Northern Light station, Kaya and Citizen Z deal with the zombie that CZ named Scampy when it followed him back to Northern Light. They eventually take him out by trapping him in a body bag and repeatedly hitting him with weapons. After they finally take care of him, they go and look for any information they can find on Black Rainbow. Once they go through all the actual files in the place, they learn that Black Rainbow is actually an old U.S. government fourth strike weapon. Sarge is able to get the radio enough power to receive the message from Citizen Z and Kaya, but it keeps cutting out. Roberta finally makes one of her most difficult choices by diverting the power from Andrew's life support to the radio so they can speak with Kaya and Citizen Z. When Sarge can't do it, Roberta offers to do the deed and gives him mercy.

Both teams put it all together: what they're up against is a fourth strike weapon that is designed to eliminate all life on Earth. That means that, despite the zombie apocalypse, there's another wave coming to wipe out everything on the planet, both living and zombified. Black Rainbow is the "reset" that Zona was working on. In order to shut down the Black Rainbow plan, the team needs to go to the launch site and shut it down with the thumbprint of the President. And so, they head out on their way to find the thumbprint of the President.


Main Cast[]

Guest Starring[]

  • Natalie Jongjaroenlarp as Red
  • Holden Goyette as 5K



Memorable Quotes[]

  • "A puppy" - JZ about a zombie

Image Gallery[]



  • The episode shows flashbacks from "No Mercy", as both episodes play out in the same location.
  • The episode features the team playing with a Kraken from "No Mercy".


Episodes of Z Nation
Season 1 "Puppies and Kittens" • "Fracking Zombies" • "Philly Feast" • "Full Metal Zombie" • "Home Sweet Zombie" • "Resurrection Z" • "Welcome to FU-Bar" • "Zunami" • "Die Zombie Die ... Again" • "Going Nuclear" • "Sisters of Mercy" • "Murphy's Law" • "Doctor of the Dead"
Season 2 "The Murphy" • "White Light" • "Zombie Road" • "Batch 47" • "Zombaby!" • "Zombie Baby Daddy" • "Down the Mississippi" • "The Collector" • "RoZwell" • "We Were Nowhere Near the Grand Canyon" • "Corporate Retreat" • "Party With the Zeros" • "Adiós, Muchachos" • "Day One" • "All Good Things Must Come to an End"
Season 3 "No Mercy" • "A New Mission" • "Murphy's Miracle" • "Escorpion and the Red Hand" • "Little Red and the WolfZ" • "Doc Flew Over the Cuckoo's Nest" • "Welcome to Murphytown" • "Election Day" • "Heart of Darkness" • "They Grow Up So Quickly" • "Doc's Angels" • "The Siege of Murphytown" • "Duel" • "Everybody Dies in the End"
Season 4 "Warren's Dream" • "Escape from Zona" • "The Vanishing" • "Keep Moving" • "Fear of the Unknown" • "Back from the Undead" • "A Nice Day for a Warren's Wedding" • "Crisis of Faith" • "We Interrupt This Program" • "Frenemies" • "Return to Mercy Labs"• "Mt. Weather"• "The Black Rainbow"
Season 5 "Welcome to the Newpocalypse" • "A New Life" • "Escape from Altura" • "Pacifica" • "Killing All The Books" • "Limbo" • "Doc's Stoned History" • "Heartland" • "Water Keepers" • "State of Mine" • "Hackerville" • "At All Cost" • "The End of Everything"