Alien: Romulustakes place 20 years after the ill-fated events that claimed the crew of the Nostromo in Ridley Scott’s 1979 filmand 49 years after the ill-fated journey of the USCSS Prometheus. Fede Álvarez bridges the gap between the two predecessor films in Alien: Romulus, which should leave every fan satisfied, and it’s all tied to the backstory of the Renaissance space station.

Weyland-Yutani is a key focus of Alien: Romulus and everything happening to the main characters is once more the direct cause of the company’s scientific negligence and lack of ethics. While you didn’t need to watch Prometheus before Romulus, knowing the following might help you better piece everything together.

Major spoilers for Alien: Romulus and Prometheus ahead!

The Prometheus Connection In Alien: Romulus, Explained

The main connection to Prometheus in Alien: Romulus is when Rain, Andy, and Tyler enter the Romulus Lab and discover theWeyland-Yutani experimentsbeing done aboard the space station.

You’ll seea tank of black droplets, separated and floating around in the water, and some dead Facehuggers in more tanks that look like they’ve been affected by some kind of sickness.

Then,CGI Ian Holm lookalike science officer Rookexplains the experiment and what the company has been up to. From the Xenomorph Weyland-Yutani recovered (the same one from the original movie that Ripley ejected), Rook and the other scientistswere able to synthesize a compound called Z-01.

Rook refers to Z-01 as “Prometheus fire,“and says the aim is to accelerate evolution in humans to be better equipped for space colonization and the various hazards that come with it.

Rook bioengineered the station’s Facehuggersfrom the Big Chap Xenomorph’s DNAin the same way David bioengineered his own Facehuggers in Alien: Covenant, and then discovered that they implant a substance in their host, a “non-Newtonian fluid” that grows a chestburster.

According to Rook, this substance isa microorganism that “can be the most destructive pathogen ever observed.“This is exactly what Prometheus has shown, that it’s a bioweapon that brings about destruction and alien infection, but also creates new life.

In another direct connection to Prometheus, Rook says Z-01"Prometheus Fire” is precisely what Peter Weyland died searching for. In Prometheus, you learn Weyland secretly tagged along on the Prometheus expedition only to then be killed by an Engineer.

This black fluid Rook synthesized into humanity’s ‘miracle’ to advance evolution in Romulus is the same genetic material asthe black goo found on the Engineer ship in Prometheus, plus Alien: Covenant has additionally shownthat Facehuggers and Xenomorphs all originate from it.

The Offspring Xenomorph, Explained

In the lab, you also see that theZ-01 compound has been tested on mice, and the results were nothing good.

After being injected with it, the mouse bursts itself like a chestburster,almost shedding its original form to evolve into a more giant mutated version that has Xenomorph partsmorphed into its body.

Rain’s friendKay, who is pregnantand badly injured from her encounter with a Xenomorph,decides to inject herself with the Z-01out of fear that she won’t make it back to their ship alive.

What this microorganism agent does is cocoon her fetus inside an alien Ovomorph egg, and shebirths a rapidly growing new human-hybrid Xenomorph called the Offspring, which is meant to resemble an Engineer species crossed with a Xenomorph.

Kay’s birthing sequence and experimenting with the Z-01 on herself is another tie to Prometheus, where the rogue android David infects Dr. Charlie Holloway with the Engineer’s pathogen, who then gets Dr. Elizabeth Shaw pregnant,and she removes an alien creature that rapidly grows into a Trilobite Facehuggerto create a Deacon with an Engineer.

The Offspring’s face and pale coloration look somewhat similar to that of an Engineer from Prometheusand director Fede Álvarez had exactly that intention with its design, sincehuman and Engineer DNA were determined to be identical.

The Offspring is also one of the most disturbing Xenomorph creatures introduced into the canon, and ended up being the most terrifying part of Alien: Romulus.

You can learn more about Weyland-Yutani’s experiments with the Z-01 compoundin the 2018 novel Alien: The Cold Forge.

The Z-01 Bioweapon’s Origin In Prometheus, Explained

Before Alien: Romulus gave an official name for the black liquid pathogen, it was simply known as the black goo, or its longer scientific nameChemical A0-3959X.91. In Prometheus, it was found on a moon calledLV-223in 2093.

A cave painting in Scotland pointed scientists to a race called the Engineers as the creators of all life on Earth. At the start of Prometheus, you seean Engineer ingesting the Z-01 black gooand dissolving into the water, the DNA strands being altered in the reaction and seemingly giving way to new life.

The Prometheus expedition, funded by Peter Weyland, who is old and dying, takes on a double agenda. Dr. Elizabeth Shaw wants to discover the secrets of the Engineers and learn more about them, andWeyland wants to find a solution to live forever.

On LV-223, the crew of the Prometheus discovers a mysterious structure with evidence of the Engineers, including their ship matching the derelict on LV-426 in the original Alien movie, along witha chamber filled with hundreds of canisters of the black goo pathogen(and a large statue of a God-like head).

Oncethe black liquid from the canisters begins to ooze out and meltdue to the temperature change in the room, you begin to see its rapid evolutionary effects.

Worms crawling in the bioweapon chamber turn intosnake-like alien creatures called Hammerpedeswhen coming into contact with the substance. Dr. Charlie Holloway gets very sick and black veins are visible all around his body. Fifield is badly mutated and turns violent (his design resembles a Xenomorphin the film’s deleted scene).

Charlie’s infected DNA causesa tentacled Trilobite alien to grow as a fetus inside Dr. Elizabeth Shaw, instantly growing into a more giant version and mating with LV-223’s last surviving Engineer to result in the more evolved Deacon Xenomorph bursting from the Engineer.

​​​​In Alien: Covenant,David drops the Engineer’s entire arsenal of Z-01 “Prometheus Fire"canisters on a planet filled with Engineer-like species to obliterate them and alter the ecology to create Xenos of various forms, likeNeomorphsand thePraetomorph.

There’s even a mural on the wall inside the Engineer chamber containing all the black goo canisters that resembles a Xenomorph Deacon, which hints that the Engineers themselves already began creating the alien species with the black goo agent long before David did in the prequels.