A new member has joined Eli and the Shane Gang! Junjie, once the protector of the Eastern Caverns, is a master of the slugslinging art of Slug Fu! But even with the power of five slingers, the Shane Gang find themselves in over their heads as they race across the 99 caverns in search of the legendary Elemental Slugs. The five Elementals are ancient slugs of great power, and the forebearers of all slugs found in Slugterra today. In the wrong hands, they could bring Slugterra to the brink of destruction. So, when an evil alliance starts hunting down the Elementals, Eli and his friends — both old and new — take off in pursuit of the greatest threat their world has ever faced!

A short cut takes the Shane Gang through the territory of the Shadow Clan -- and try as they might not to, they are discovered and captured by the mysterious creatures. Just when it looks like our heroes are done for, they are helped out of this jam by a most unlikely savior.

Tad's hypnotic slug Pieper has gone megamorph, his gang of supporters all have Gattler blasters and Tad's control over his new ghouls is stronger than Dr. Blakk's ever was. The Shane Gang are under non-stop ghoul fire as they struggle to put a stop to Tad's plans and the mass ghouling of slugs once and for all.

After a wild ride on the mysterious Flumes, the Underriver that runs beneath all the Slugterra, the Shane gang find themselves dropped into a sea cavern, where they are promptly shanghaied into the crew of the Pirate Captain Malvolio Drake.

Tad is missing after the slug-out with the Shadow Clan, so the Gang sets off without him to investigate reports of slugs disappearing. The mystery deepens as the trail of slugs leads straight to Dr. Blakk's old stronghold!

The gang has to trade one of Eli's prized his slugs for some new gear, but when Eli has second thoughts and goes back to get his slug, they learn its been sold to Dr. Blakk!

When the hooligang enters the Quiet Lawn Cavern and think no one is tough enough to stand up to them, they get proven wrong by Eli and his gang.

Eli wants to enter the Slug Run, despite being told he isn't experienced enough. He finds himself up against some tough opponents, including Vance Volt, who works for Blakk.

Long thought to be merely a legend, an Enigmo Slug has finally been spotted. The bidding is high for this, the rarest of all slugs, and so is the competition to be the first grab it! Eli and the gang actually beat Slugterra's most vicious slug hunter to the prize--only to find that the hunter is now hunting them!

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!

As the Shane Gang returns to the 99 caverns from their Eastern adventure, they find Gateway Cavern overrun with slugs. In the Shane Gang's absence, the Shadow Clan took a different approach to protecting the caverns, putting slugs before the needs of people and it's up to Eli and the gang to restore balance.

Eli and the Gang find a way to take Junjie back home to the Eastern Caverns and discover trouble waiting for them when they arrive.

15-year-old Eli Shane is just a regular kid from the suburbs, except for one thing: he comes from a long line of Shanes, each of whom has made the journey from the surface to protect Slugterra and the slugs that make the underground world so special. Now its Eli's turn to be Slugterra's next Shane -- whether he's ready or not! Unfortunately, the slugslinging tournament he enters to prove that he's ready, quickly shows that he's not! So when word of this new Shane reaches the ears of the nefarious Dr. Blakk, he's not too worried... yet.

Eli has added some awesome new slugs to his arsenal: the extremely powerful Elemental Slugs. But in order to control them, Eli must learn Slug Fu--the ancient form of slugslinging that Junjie mastered in the Eastern Caverns. Slug Fu is the art of guiding and controlling a slug in battle--a skill that only the greatest slugslingers can master.

In a climactic battle, Junjie and Eli confront the Emperor and the Dai-Fu as the fate of the entire Eastern Caverns hangs in the balance!

The Shane Gang takes Tad under their wing, training him to become a great slugslinger with Eli's old blaster. Their training is put to the test when the Gang brings Tad to answer a distress call that leads to a showdown with the Scrap Force and the Shadow Clan.

When Eli and the gang enter the Deadweed cavern, they discover a huge amount of El Diablus Nacho, the Dark Water Dr Blakk uses to brainwash innocent slugs.

Upon returning to the Outlaws’ jungle camp, the Shane Gang suffer a sneak attack from the Emperor’s Underlord Holt, who steals almost all of their slugs and loads them onto the Dragon Train for transport to the Emperor. With precious few slugs to use as ammo, the Shane Gang must be extra resourceful to get them back.

Eli Shane wins his battles and gets a new slug. It's time for the finals, but Eli is beaten with a dark slug given to his opponent by Dr Thaddius Blakk.

Eli doesn't believe in ghosts -- until he enters Deadweed cavern! But it turns out Eli's first instinct was right. What lurks inside Deadweed is far more evil than ghosts, its El Diablus Nacho, after a supply of the dangerous Dark Water that Dr. Blakk uses to turn innocent slugs into Ghouls.

In order to reach the Emperor of the Eastern Caverns, Eli and Junjie pose as Underlords to enter the Tournament of Underlords. But when Holt turns up to expose the Shane Gang, it's up to Pronto to stop him.

When even Kord can't find a way to fix what's wrong with the new upgrades to the Shane Gang's Mecha Beasts, it's time to go to the source: the wondrous Mecha Forge! Hoping to find the cause of the glitch, the gang instead uncovers a huge conspiracy--hatched by Dr. Blakk!

Pronto is thrown in jail on trumped-up charges by a corrupt judge, and the only chance to break him out is Eli making a one-in-a-million trick shot. Only one slinger in all of Slugterra can help Eli make a shot like that—Mario Bravado. Finding the formerly-great-but-now-washed-up Mario is easy. Getting him to help is something else entirely.

A fun trip to the mall cavern turns un-deadly when the place is over run by the zombie-like victims of the Zombus slug. With Pronto zombified (not entirely a bad thing, the others kind of like this new, quieter, more monosyllabic Pronto), the rest of the Shane Gang must find the mysterious Mr. Saturday who controls the Zombus slugs -- and find a way to stop him.

The four members of the Shane Gang think they've found the fifth in Twist, a street-smart kid who volunteers his help when the gang needs it most on a mission gone wrong. However, Twist harbors a dark secret that could doom the mission — and the Shane Gang.