For every zombie story somberly depicting the bleakness of humanity’s extinction, there’s a zombie story with a slide-whistle sound effect somewhere. The Zombies mode of Treyarch’s Call of Duty: Black Ops series offers the familiar format of surviving, evading, and slaying waves of the undead with increasingly powerful weapons, but the backstory—a spiraling canon of mad scientists, time travel, exploding monkeys, and a zombie George Romero, among other things—places it in a special 'zombie nonsense' category. With the release of the Zombies Chronicles DLC for Black Ops 3 last month, several remastered maps from the World at War, Black Ops, and Black Ops 2 Zombie modes offer a return descent into the timeline’s absurdity.

See for yourself in the below timeline charting what amounts to the 'original' Zombies story arc. Those quotes hang heavy, because as you’ll soon read, things get a little spaghettified. The information gathered here was sourced from both community-created interpretations of major events and by squinting really hard at Treyarch’s official ancient scroll .

It’s pretty much this rock’s fault. Meteors of a glowing material named “Element 115” crash onto Earth throughout the early millennia of human history. Besides its sinister rave lighting and “oooo” noises up close, Element 115 provided superpowering properties and would both eventually speed up development of devastating weapons and address the pressing need for branded, refreshing beverages long before Coca-Cola started selling your name on cans. Oh, and it also reanimated dead people into zombies. When Germany found out about Element 115 in the early 1930s, it decided to investigate, likely thinking, “Here’s an otherworldly space rock we can absolutely trust.”

Actually, it’s pretty much this guy’s fault. Among the German scientists checking out their new haul is Dr. Edward Richtofen, a man dedicated to his work with occasional trifling bouts of murderous hysteria and bloodthirst. He joins Group 935, an organization studying Element 115 and founded by his colleague Dr. Ludvig Maxis. He also joins the Illuminati because he presumably had extra space to fill on his business card. He soon plots to betray his co-workers by wielding the power of Element 115 for himself and destroy the world with legions of the undead at his command. You can’t write exquisitely detailed villain motivations like this anymore. Uh, maybe you can.

Richtofen volunteers himself to test a 115-powered teleportation device. He teleports to the Moon, discovers an ancient alien pyramid, and starts hearing evil voices. Also, it turns out the structure charges up power when things die beside it. Following the ironclad logic of obeying any weird moon architecture you encounter, Richtofen returns to Earth and starts zapping unwitting victims to a quick demise on the Moon to feed his new overlord. He keeps things quiet both to avoid rousing Maxis’ suspicion and because shouting “BLOOD FOR THE LIGHT-ABSORBING POLYHEDRON” during each teleport would probably stir some gossip around the water cooler.

Hellhounds were puppies born from a pet dog who was teleported as an experiment. How did this happen? Simple: The pet dog was Fluffy, owned by Samantha, Maxis’ daughter who was inexplicably allowed free access to a secret, ultra-secure research facility. When Fluffy popped back into reality sporting glowing demon eyes and a half-melted face, Samantha ran inside the teleporter chamber after her. (Who designed the security for this place?) Distraught, Maxis pursued Samantha into the teleporter. Seeing his chance, Richtofen flushed them down the temporal tubes by teleporting both father and daughter at the same time. Fluffy runs around and bites people. Samantha blinks onto the Moon, encounters the alien building, achieves her little-girl-in-horror destiny of becoming absorbed into it, and finds out she can remotely control the undead. Maxis beams into a place that looks like a Tangerine Dream album cover, dies, and learns how to become a computer. Duh.

Zombies. Remember zombies? This is a mode about zombies.

Richtofen teams up with some test subjects he brain-wiped and teleports across space and time to wrest the alien power away from Samantha. First stop: a 1963 Soviet spaceport where they catch up with Gersh, a glowing ethereal blob that’s actually a former scientist stuck between dimensions after his assistant Yuri tricked him into turning on a miniature black-hole generator before he could properly wash his hands or something. Richtofen learns that he needs to head over to Siberia and pick up something called the Golden Rod, the first component needed to uncork Samantha from the lunar pyramid. Gersh then boots Richtofen and his group into a temporal rift and Dr. Manhattans out of perceived existence. Now, things get a little weird.

Meanwhile, John F. Kennedy, Richard Nixon, Fidel Castro, and Robert McNamara fight zombies in the Pentagon. The only exception to this otherwise normal proceeding of U.S. politics is the sudden appearance of Yuri. Under Samantha’s sway and disgruntled over his thankless job of launching monkeys in space, he figures the perfect idea of revenge involves strapping on oversized goggles and trying to steal Kennedy and co.’s weapons by running into their bullets. Again, mostly standard Pentagon stuff.

Richtofen’s crew teleports forward in time to an abandoned Group 935 Siberia facility in 2011 and get stuck in a sealed room while Danny Trejo, Sarah Michelle Gellar, Robert Englund, and Michael Rooker fight an undead George Romero. The obvious context is a zombie film shoot gone awry, but I like to pretend Machete, Buffy, Freddy Kreuger, and Yondu accidentally teleported to an alternate timeline where they take over the souls of their actor counterparts, because we’re way past the point of in-universe rationality. Richtofen convinces the four sophisticated thespians to recover and hand over the Golden Rod through a pneumatic tube attached to the room’s vault-like door. He then makes a quick reverse jaunt to 1956 and picks up a mini-Element 115 boulder called the Focusing Stone from an altar in Shangri-La—you know, the same Shangri-La from legend programmed into everyone’s phone GPS by default. With both stone and rod, Richtofen’s vaguely phallic preparations are complete.

Richtofen and his group teleport to the Moon station housing the alien building. He uses the Golden Rod to swap bodies with the trapped Samantha and take control of the zombies. Maxis-tosh contacts Samantha and the remaining accomplices through the station’s systems and pleads for them to stop Richtofen once and for all. They hatch a foolproof plan to sever Richtofen’s connection to the pyramid by firing the station’s missiles at Earth. The Earth explodes. Everything is back to normal.

It’s pretty much Malcolm McDowell’s fault. Well, not the actual guy, but the being using his rugged features to pull strings from the shadows. He’s a Keeper, a mystical protector of time and space at war with the Apothicons, evil Keepers from a hellish dimension where “orthodontics” apparently isn’t a word. All of this becomes slowly revealed as the Zombies timeline continues, including a Metal Gear-style web of influence involving the initial appearance of Element 115 on Earth just to mess with humanity, multiple copies of Richtofen, giant robots, and a scheme to resurrect ancient zombie-eating dragons. The story goes on, but the more important thing to realize is every time you crack open a freshly chilled Perk-a-Cola, you're experiencing the flavorful touch of a pandimensional, intergalactic war between corrupted demi-gods. And zombies.