In the pre-dawn hush of April 20, a man burying his wife in the woods witnesses what looks like a meteor crash nearby. Investigating, he discovers it’s not a rock at all but an alien capsule containing a gigantic Space Bong, which he pockets and takes with him. Alistair McDowell [Peter Stickles], a scientist at the Space Institute who has been tracking the comet, locates the capsule in the woods and quickly concludes that this is no meteor. He is confronted by Larnell [John Patrick Jordan], a Black Belt who initially doesn’t recognize him—a wink at Alistair’s second recasting—who immediately fills the air with conspiracy theories about James Cameron being an alien and government agencies being corrupt. Larnell explains he’s living off the grid and training with a supposed “Ninja Master” named Wong Dong, who is really just a car stereo thief. He convincingly urges Alistair to help him search for what he believes is an alien bong, pointing to the marijuana residue on the object as proof.
The Killer [Irwin Keyes], a veritable husband with a chilling edge, carries the Space Bong to a small smoke shop co-owned by Brett [Brian Lloyd] and Bachman [Mitch Eakins], and sells it. It’s revealed that the alien marijuana found on the meteor has spread like a rash across the Killer’s skin, and Brett soon calls Alistair to glean more about the mysterious Bong. In a back room, Bachman lights up Space Bong, which comes to life and pulls him into Space Bong’s Bong World, a surreal realm where he’s menaced by mostly nude women.
Back at the shop, Alistair and Larnell arrive to inspect the Bong. Brett notices the alien fungus has grown on items touched by the Killer, and Alistair finds the same phenomenon spreading through his meteor samples. Rabbit [Sonny Carl Davis], a practicing priest, arrives for a scheduled “study session” with Bachman, who has vanished. Brett’s ex-girlfriend Luann [Robin Sydney] stops by briefly, raising tension from the past, while Rabbit is tempted into smoking from Space Bong, which reveals its aim to take over Earth.
Larnell suggests turning to his grandfather Cyril (a medical marijuana doctor going by Dr. Weed) who arrives with his assistant Nurse Hookah [Christina DeRosa]. Cyril, along with Evil Bong Eebee [Michelle Mais], were ditched by the gang in the Amazon after defeating King Bong, and they’ve since become friends and business partners. Space Bong insults Eebee, prompting her and Cyril to team up with the others to thwart the alien intruder. Larnell, Alistair, and Eebee venture into Space Bong’s Bong World while Nurse Hookah holds Brett hostage, per Cyril’s orders, in case things go wrong.
Inside Bong World, Larnell and Eebee discover Rabbit and Bachman hooked up to alien contraptions used to farm their sperm. Alistair finds himself trapped in one of the machines as Space Bong tries to prove he is an invader with a peaceful façade. Outside, Space Bong convinces Cyril that he is not an invader but a peaceful visitor. Brett overpowers Nurse Hookah and follows them into the Bong World, finding Rabbit and Bachman milked dry and delirious, with Bachman covered in the alien fungus. The trio locate Eebee and Larnell fighting to free Al from the sperm extractor, which Space Bong values highly due to Alistair’s intellect.
Larnell uses his fighting skills to fend off the nude alien women and free Al, but the gang remains trapped inside Bong World. Eebee suggests a daring reverse escape: fuse Space Bong’s “female units” with the smoke from a fungus-drenched Bachman, whom they set ablaze. The resulting joint moment ignites power, causing Space Bong and his entourage to explode and returning the group to Earth.
Some time later, Brett and Luann are back together, and the gang lounges at the shop. Larnell orders pizza, and Velicity [Amy Paffrath] walks in with the pie. Velicity explains she lost her income after they toppled King Bong and Cyril stopped employing her, so she decides to stay with Larnell. Brett, however, still bears some of the alien marijuana fungus, much to Luann’s dismay. In the final scene, Cyril and Nurse Hookah find the original meteor, the crash site now overgrown with the alien weed.
