Just when the evil Dr. Blakk has been defeated and it seems like Eli Shane’s duties as protector of Slugterra are getting easier, a new danger emerges from beyond the 99 caverns. Eli and the Shane Gang rush to the rescue, but nothing can prepare them for what they encounter: a slug that can do something no one in Slugterra has ever seen — or heard — a slug do before! Traditional slugslinging no longer applies — Eli will have to engage in a very different kind of duel to save Slugterra...and himself!
The film begins with Pronto telling the story of how the Shane Gang defeated Dr. Blakk and his ghouls (in the wrong way!), as Trixie films him. They are on their way to the Caverna Mall, but when they arrive they are marauded by the Scrap Force Gang and Boss Ember, who have escaped the junkyard. Boss Ember challenges Eli to a duel, but Eli is surprised when he shoots a Megamorph slug (an Armashelt), which Eli warns to be unstable, but he shoots it anyways and no sooner does Eli sling Burpy to stop the darting slug. The gang then frees the mall-cops, and the Scrap Force are placed under arrest. However Eli feels it is his duty to find out how the others megamorph their slugs when only the Shane Gang could.
A strange group of slingers with masks are loading a truck with Fandango Slugs when the Shane Gang intervenes. They have a strange, large creature resembling an ice creature from Snowdance, but they battle them until they leave town. Coincidently, they are the ones who have ghouls and leave immediately when they see Eli's Infurnus, Burpy, and then are chased by the Shane Gang. As they leave, King tells them that they just came, never seen before, and stole the Fandangos. He believes they came from the East out of the Outland Reach, in where Pronto explains that far East is the "End" of The 99 Caverns in the Outland Reach, where no human, Molenoid or Cave Troll has ever ventured before. The Shane Gang follow the strange marauders to the far East cavern on their Mechas, which is a rocky, empty terrain with walls of mountain and some lava residue.
When they arrive, a strange figure emerges from the fog of a portal, who they think is Dr. Blakk, but calls himself 'The Dark Slinger' and spares not a minute to shoot what appears to be a ghouled Boon Doc. Eli shoots Burpy, his Infurnus, but there's an flash of light when the slugs collide, and an ghouled version of Burpy appears, and shoots himself back at Eli after being transformed by the Goon Doc. Eli and the Gang retreat, while Burpy shoots Smashteroid at them, Eli then quickly shoots Burpy with Doc, and cures him. Doc is shot many times, before he is knocked out and sucked into a Slug Tunnel. Eventually Eli decides to use Burpy on the Dark Slinger, but the Dark Slinger tells Eli that he's not the only one with an Infurnus & shows him a ghouled one. Shocked that there's another Infurnus, the Dark Slinger tells Eli he "doesn't got out much", and then they shoot each other with their Infurnaces, equally matched they cause an explosion which knocks Eli down and a sand cloud to fog up to area, at which point the Dark Slinger has Eli at gunpoint with the Goon Doc loaded. And the Dark Slinger... wait for it, the Goon Doc reveals he's the one causing the attack & hosting the person he calls "The Dark Slinger".
Eli, now at gunpoint by the Dark Slinger, and the sand clearing up, the Goon tells Eli that he has the ability to control people, but his Dark Energy wears down, so he needs a new host, one that knows their caverns, and tells him that once he falls, everyone else will follow. Then, the Dark Slinger shoots Eli with the Goon, while the Dark Slinger falls unconscious and Shane Gang look on in the distance, and Burpy goes after Doc. Then, the Goon who now has control over Eli's speech, tells the marauders to protect him from the Gang until he has full control.
Inside Eli's mind, the Goon tells Eli he sensed 'corrpupted energy' from the 99 caverns, and wanted to see who other than him could make ghouls, so he used Fandango Slugs and a Terraportal to get SlugTerra, but when he came there were no ghouls in sight. Eli begins to tell him that there were, but they cured them, that's when the Goon realizes Eli was telling the truth, when he started looking into Eli's memories of Dr. Blakk & the Darkbane. Eli assures that Dr. Blakk & the Darkbane were defeated & gone for good, and that he's too late.
Then the Goon stops him and says that they aren't gone & that they're still alive. The Goon then gets angry and tries to possess Eli again. But Eli fights him away, and the Goon begins to grow to a giant size in anger. Eli shoots a Thresher at him, but it immediately turns into sick Floppers, as well as the rest of his slugs temporarily. The Goon is now pursuing Eli in his mind, trying to catch him and possess him completely. The Goon senses the portal closing, so through Eli's body, he orders his marauders to deliver the Fandangos to the other side, or the portal will permanently close and his entire army won't make it. But Eli fights him back within his mind, bringing him back to the coma-state. The battle continues, Eli's friends are chasing down the crew taking the Fandango Slugs, but the Goon convinces Eli that he is slowly taking over his body. When Eli says that he wishes he had Burpy, the Goon, now growing even more to overpower Eli, tells Eli that he has an Infurnus, yet he doesn't even know its significance, Eli then says he knows how important Burpy is.
However the Goon then reveals that there is only one Infurnus for every Cavern (Slug World) and that whoever has an Infurnus is considered to be the protector of their Caverns. He then starts telling a little story about the champion of the Eastern Realms named Junjie and how he was just like him, a master with an Infurnus, and that he was unbeatable, and that once he was possessed as he served his purpose. When Eli finally can't take it anymore, the Goon finally possesses his body and turns him into a zombie-like creature with pale skin as the Goon awakens in his new body, and Junjie, who is still unconscious turns back into his original state as a normal slinger, who appears to be of a South-Asian orient or "The Far East" of the caverns.
After Trixie, Kord, and Pronto battle the marauders and unsuccessfully make it through the portal (only to stay where they were) it turns out Pronto rescued the Fandangos when Trixie and Kord were distracted. Just then, Eli (The Goon) "awakens" and the three are shocked to see his appearance changed. Kord tells Trixie and Pronto that it isn't Eli, but the Goon on his shoulder possessing him. The possessed Eli is pointing a ghoul in his blaster at his friends, but just then Eli fights back in his mind, shooting away from his friends as the last straw continues. But the Goon doesn't stop, he continues to overpower Eli, as the possessed Eli shoots slugs at his friends, too powerful for them to handle. After beating Pronto, Kord, and Trixie leaving them on the brink, Burpy, who has found the suctioned Doc, returns, ready to save Eli. Then, Burpy and Doc enter Eli's mind in their transformed slug forms, Burpy has a final battle with the Goon and while Doc heals Eli. The battle ends with Eli blasting the Goon with Doc; but sends the Goon hurtling down the Slug Turnnel Doc went down. Later the Goon is shown swearing that he will build a new army, meanwhile Eli hears his voice in his mind.
The final scene closes with Trixie saying they've got some work to do, proclaiming a possible new season of the series, and the Shane Gang finally at peace...for now. But just as the gang shares a moment, Kord exclaims, 'Ok...But...what are we going to do about... him?' and points to Junjie who is now awake, an Infurnus on his shoulder, bowing down graciously and smiling to the Shane Gang for saving him.
- The Scrap Force
- King of Sling
- Dr. Blakk (Appears in flashback(s))
- Brimstone (Appears in flashback(s))
- Millard Milford & "Mall" Security Slingers
- Darkbane (Appears in flashback(s))
- Shadow Clan (Appears in flashback(s))
- Blakk Guards (Appears in Pronto's story)
- Will Shane (Mentioned only)
- The 99 Caverns
- The Eastern Caverns (Appears in flashback(s))
- The Deep Caverns (Appears in flashback(s))
- This movie marks the first story of Season Two.
- During post-production the film was originally going too be titled "Slugterra: The End and the Beginning".
- In the movie's first poster, Eli's blaster is equipped with the Double Barrel, though a Megamorph Fusion Shot has been seen in the movie.
- Additionally, the blaster has its Accelerator equipped.
- The ghoul slug being shot resembles the Goon Doc, the ghouled version of Boon Doc, although this particular Goon Doc seems more enhanced and/or corrupted than the usual ghoul. This ghoul could also be mega-morphed.
- The slugs and ghouls that are already seen to become Megamorphs in the series are applied in the opening theme song.
- The opening theme song is changed of images and characters.
- A Darkbane shooting a Attacknet is seen.
- El Diablos Nacho is seen in his True Form.
- Billy is absent.
- The opening theme song Dr. Blakk is hardly seen.
- Blakk Shots in the start of the theme song a Hop Jack but in this a Harmashelt, Grimmstone and Hop Jack is shot.
- Usually Blakk shoots after Eli but instead Blakk shoots first.
- The Importance of the Infurnus is revealed
- When Eli was possessed, most of his slugs (Joules, Spinner, Banger and Chiller) turned into ghouls, but didn't mega morph, except for his Rammstone (possibly Bludgeon) who remained a mega morph when he was & wasn't a ghoul.
- It is revealed that The Goon was from the Eastern Caverns.
- Slugterra: Ghoul From Beyond was nominated for the Canadian Screen Awards, CA in 2015 for Best Sound in a Comedy, Variety, or Animated Program or Series. 
- In Disney XD Asia, the scene when Kord shoots his Hoverbug at a Marauder in close range is cut out due to being too violent.
- Eli asks The Goon "How do I kick your tiny butt out of my head?" is shortened into "How do I kick you out of my head?" by Disney XD Asia.
- The scene when the Blakk Guards are ghouling the slugs is similar to the one in "Dark as Night".
- Trixie mentions The Scrap Heap, where The Scrap Force used to be during "The Hard Part".
- Pronto mentions The Outland Reach, which has been mentioned in "King of Sling".
- Burpy turns into a Darkfurnus since "What Lies Beneath".
- The scene when Dr. Blakk breaks out of Stalagmite 17 with the help of Darkbanes is from "Back to Blakk".
- The final battle against Dr. Blakk and the Darkbanes is from "Light as Day".
- Boss Ember's Armashelt can't handle the megamorph speed but it was in megamorph protoform.
- Doc heals Bubbalash, Dark Urchin and Thrasher but then Lariat, Hop Rock, Arachnet and Rammstone appear.
- Stinky is shown as a regular slug, despite mega morphing in Light as Day.
- There is a marauder without blaster.
- While inside Eli's Mind, the Goon can be seen changing from a megamorph to a normal Goon Doc then back several times.
- Pronto's Thresher looks like Butch.
- In some scenes Bluster is a Guardian Slug.
The One- Hour Film had been confirmed to premiere in March 30, 2014 on Disney XD Canada. The Film is airing on Disney XD in Poland, South Africa, Turkey, the Middle East and Greece August 16 or/and 17. Ghoul from Beyond airs on Disney XD in the US August 20 2014.
The Slugterra: Ghoul From Beyond DVD will be purchasable on June 10, 2014 on Amazon and other realties. The Film was in retailers price for $14.70 with a bonus of a Slugisode called "Burpy and Friends Take a Dive".