As the gang rolls into Roswell, New Mexico (let's say RoZwell), they encounter something they can't really explain: a flying saucer that whips over them and then disappears into the horizon. Is the truth out there?
This is -- heh heh -- Dan Scully (Doug Jones!). He tells the team that the zombie apocalypse was actually instigated by aliens who live in the hollowed-out spaceship that we think of as Pluto. Dan also tells them not to believe anything Bernadette says.
When the team is told there's a secret base within the base, they head into a room that turns out to be an elevator that descends several miles underground at top speed. It looks fun, actually. Until …
... they come across a zombie alien! The team is under attack by a creature that was once an alien but is now a zombie version of an alien! Holy smokes! The team blows the holy hell out of the thing and it explodes all over the place.
Addy discovers an advanced technology computer that has control of the entire base ... and contains a lot of video of Murphy. More interestingly, it also has a star map and references to something called "Zona." Where might you have heard about Zona before?
After Scully (heh) explains that the "aliens" in the base were just zombified test pilots, he succumbs to his wounds and the team gives him mercy. Bernadette then tells the good people of Roswell that they'll have to wait a little bit longer for that mass exodus off the planet.