The team travels to Mississippi in 1863 to try and prevent zombies created by a future bioweapon from changing the course of the war.
Tropes:
- An Aesop: The episode doesn't shy away from showing just how bad racism and slavery were during the Civil War.
- Air-Vent Passageway: How Ray manages to escape from the galley whilst zombie-Mick is just outside the door.
- Antagonist Title: The abominations are the titular zombies. In a way, it also refers to the prejudice against African-American people during the era.
- Arson, Murder, and Jaywalking: Mick when he's filling Ray in on the situation.Mick: We were attacked by zombies. And someone put sprouts on my sandwich.
- Artistic License – History: When Sara and Nate find him, Grant is fully dressed, buttoned up in his uniform. He was somewhat infamous in the officer corps and beloved by his men for being something of a slob (one of the men), typically walking around with his coat unbuttoned and his shirt untucked.
- Artistic License – Pharmacology: Both Professor Stein and Ray repeatedly refer to the zombie cure Ray came up with as "vaccine". Since the drug is meant to cure someone who has already been infected with the zombie virus, it's not a vaccine rather than an antiviral drug
or a virucide. - Asshole Victim: Mr. Collins the slave-owner, and all his staff, are killed by the zombies.
- Bad Future: We get a brief glimpse of one where the zombies, combined with the Union carrier dying prematurely at the start of the episode, leads to the North losing the Battle of Vicksburg, and subsequently the war, leading to the Confederacy successfully seceding.
- Batman Gambit: Amaya deliberately provokes a white slave owner, knowing that he'll take her to where Jax is being held. When they get there, she beats the guy up and frees Jax.
- Being Good Sucks: Jax is reluctant to help any slaves afraid it might screw with history. He changes his mind once he gets whipped as one.
- Big, Stupid Doodoo-Head: While taunting the zombies into chasing him, Nate calls them "Ya big dummies!"
- Brain Food: While he and Ray are fleeing Zombie-Mick, Dr. Stein glibly remarks that if Rory intends to eat their brains he's in for quite a feast, given his and Ray's combined intellects.
- Brick Joke: Mick complains early in the episode that someone (Ray) put sprouts on his sandwich. At the end of the episode, Ray brings the recently de-zombified Mick a burger and promises there are "No sprouts" on it.
- Brief Accent Imitation: Amaya pretends to be a Southern Belle for a few scenes, although, given her skin color, this fails to sway the white Southerners.
- The Chains of Commanding: Sara and Grant commiserate over the burdens of being a leader, knowing that they may be sending their people to die.
- Chronic Hero Syndrome: Amaya cannot ignore anyone in need, even when told that it could damage the timeline. Justified, as she's trained as a superhero, not the Time Police.
- Darker and Edgier: By far the darkest episode of the entire series so far. Not surprising, given the subject of slavery.
- Decapitation Presentation: In order to convince him of the threat the zombies pose, Sara presents the still living severed head of a Confederate zombie to General Grant.
- Devoured by the Horde: The zombies eat most of the Asshole Victims above.
- Double-Meaning Title: The title refers not only to the Zombie Infectees, but also to the racism that was prevalent during the time period visited in this episode.
- Face Your Fears: Prof. Stein's main arc this episode is to overcome his fear of zombies.
- A Father to His Men: Ulysses Grant is depicted as a general who understands the burden of being in command, as he shows great care for his fellow army men.
- Fearless Fool: General Grant states that Nate is either the bravest man he ever met or the dumbest.
- Fighting Your Friend: Prof. Stein and Ray have to deal with the Zombie Infectee Mick throughout the episode.
- Folk Hero: The Vixens are revealed to be one. When a slave sees Amaya's amulet, she recognizes it as an artifact worn by heroes and then rallied the other slaves behind Amaya and Jax despite their initial skepticism.
- Gory Discretion Shot: Mick caving in a zombie Confederate's head with a boulder happens just below the frame. We still see a big ol' blood geyser, though.
- I Have You Now, My Pretty: One slave-owner believes that Mr. Collins has "other" plans for Amaya.
- I'm Mr. [Future Pop Culture Reference]: Nate refers to himself as "Colonel Sanders" when meeting Ulysses Grant.
- Kill It with Fire: How Jax deals with the zombies that attack the plantation.
- Laser-Guided Karma: Mr. Collins got what's coming to him after refusing to help Jax and the black slaves to arm themselves against the zombies.
- Locked Out of the Loop: Stein and Jax still haven't told the team about Future!Barry's dilemma.
- Mood Whiplash: The episode switches back and forth between the horrors of slavery and corny zombie action.
- Not Using the Zed Word: Stein tries to invoke this, but even he falls prey to it.
- Our Zombies Are Different: Confederate zombies created by a future bioweapon, that is. They fall into Plague Zombie methods via the TX-90 bioweapon, with decapitation not killing them. However, infected living can become examples of Technically-Living Zombie, and can be cured with an antidote. Both are also examples of Flesh-Eating Zombie. When Rory is infected, although he attacks Ray and knocks him out, he doesn't proceed to eat Ray, he just leaves him lying there and wanders off in search of Stein.
- Passing the Torch: Mick gives Ray Snart's Cold Gun to compensate losing the ATOM suit, choosing him as his new partner.
- Politically Correct History: General Grant has no problems whatsoever accepting the fact that Sara, a woman, is the leader of the group, and he even gives her some respectful advice on leadership.
- Pre-Mortem One-Liner: Jefferson delivers one to the horde of zombies right before molotoving them with an oil lamp.Jax: Party's over!
- Screw the Rules, I'm Doing What's Right!: Jax and Vixen free all the slaves on the plantation, even though it risks the mission.
- Shout-Out: Stein calls Mick a "Walking Dead". Further, the drug that causes the outbreak is called "TX-90", similar to the Season 1 finale of the TV series titled "TS-19".
- Slavery Is a Special Kind of Evil: The ugliness of African-American slavery is shown, and two of the African-American main characters have to deal with it.
- Sliding Scale of Idealism vs. Cynicism: Despite the horrible things that happen within the episode, both Jax and Stein still agree on that it's better to look at the good side of humanity instead of focusing on the bad.
- Taking You with Me: A non-fatal example. Nate, knowing that he could "metalize", allowed himself to be Zerg Rushed by the zombies atop of a box full of TNTs.
- A Taste of the Lash: As expected, when slavery is involved.
- Title Drop: Done courtesy of Ulysses S. Grant.
- Too Dumb to Live: Quite literally, Mr. Collins, when refusing to give Jax and the slave some weapons to help him fight off the zombies out of pride. Surely enough, he quickly gets overwhelmed, and still has the gall to beg them for help. Of course, Jax barely bats an eye.
- Tragic Keepsake: Mick kept Snart's cold gun in a box until he gives it to Ray as gratitude for curing him from The Virus.
- Vagueness Is Coming: We hear a bit of future Barry's message: "A war is coming."
- Watching Troy Burn: Jax paused for a moment to see the slave plantation burn before leaving with Amaya and the freed slaves.
- What Measure Is a Mook?: One of the series' most blatant applications of this trope. Jax repeatedly tells Vixen about the importance of not interfering, allowing a woman at one point to be whipped (and possibly killed). Yet the episode begins with him nonchalantly killing a group of Confederate soldiers (who subsequently are reanimated as zombies), any one whom could have originally survived the war and had an impact on modern-day history.
- Whole-Plot Reference: The episode is basically Django Unchained meets Pride and Prejudice and Zombies.
- Why Did It Have to Be Snakes?: Stein is even afraid of the mere word zombies.Ray: What's with your irrational fear of zombies?
Stein: It's not irrational, he's a ZOMBIE! - You Called Me "X"; It Must Be Serious:
- Sara is quite irritated when Stein calls her Sara instead of Miss Lance. It's because he is distracted by Future-Barry's warning, though he covers it up by simply saying he is turning a new leaf.
- This episode marks the first time Mick calls Ray by his first name, when the latter is trying to administer an antidote for the zombie virus to the former.
- You Will Be Beethoven: Henry Scott is supposed to steal a set of Confederate battle plans and get them to Grant, but he gets killed by zombies. So Jax delivers them and claims to be "Henry Scott", meaning that Scott's place in history remains unchanged.
- Zombie Infectee: Mick gets infected with the virus.
