Give a quick summary of Prometheus to someone who hasn't seen it, please.
During the time of Weyland-Yutani's growth to power, various prehistoric dig sites all across Earth are found to have what turn out to be star maps, suggesting a visitation by some alien precursors. WY funds a trillion (yes, trillion) dollar expedition to the star cluster where the map points. It is attended by an early android, the daughter of WY's founder, a Ellen Ripley clone for that redhead appeal, her husband, the ship pilots, and two very inconsequential fuckers.
They arrive at the planet the star chart points out and quickly discover signs of artificial construction. They find glyphs reminiscent of Proto-Indo European, weird canisters, and a hologram that shows something horrible happening to the original inhabitants. Investigation causes the canisters to open and release a weird black goo, which then coalesces into weird life-like things. The things kill the inconsequential fuckers.
Stuff happens, and it turns out Not-Ripley's husband was exposed to the black goo (By the android), so he commits suicide by cop against the WY founder's daughter. Except oh no, he and Not-Ripley banged, so she's impregnated with some...thing. WY goes all "preserve the specimen!" and put her on lockdown.
Also, the actual founder of WY, who's old as fuck, was on the ship and gets revived. He's here to try and find the prognators of humanity so they can save him from death, but his daughter would rather he die so WY goes to her. The android finishes deciphering everything and wakes up the one surviving prognator, a 7.5 foot tall hairless albino called the Engineer. He looks upon the people who woke him up and promptly goes crazy, decapitating the android and killing the WY founder as he demands immortality.
Meanwhile, Not-Ripley escapes and uses an automatic surgeon to abort the proto-facehugger growing within her, in what is probably the film's best scene. But then, the Engineer tries to escape the planet and go to Earth to presumably spray it with black goo and exterminate humanity, because they hate us for some reason. This is stopped by the crew of the human ship by fatally ramming the Engineer's ship, which falls on the WY founder's daughter.
But the Engineer survives and tries to kill Not-Ripley again! Fortunately, the proto-facehugger survived the abortion and shows up just in time to hug his face. Not-Ripley retrieves the head of the android as the only other person to talk to, and steals another alien ship to seek out their homeworld, because she's "still searching".
And then! Post-credits, a proto-xenomorph bursts out of the Engineer's corpse. The end.
Also, everybody in the movie is annoyingly religious for folks searching out a race of aliens who they think created humanity. It's not the worst film ever and has some good moments, but on the whole is below par for Ridley Scott.