Summary: Eli and the Shane Gang become trapped in caverns underneath SlugTerra and discover a new type of danger that is threatening to escape.

Summary: Quentin, a mad scientist was experimenting with Roboslugs, a new generation of slugs which has the abilities of all the slugs of slugterra. He was running mad using the Roboslug in the town. So his sister ringed to the Shane gang to seek help from them. They end up with him in a duel in which Eli defeats him using the Enigmo slug. This was because Enigmo was a rare one and only a few people have seen it transform. As a result, Quentin didn't know about the abilities of Enigmo slug. He flees and returns with a giant robot and defeats them. Proud that he has defeated the Shane gang, he leaves the place. After the duel, his sister tells him about her brother's flashback that when he was a young boy, he went to a field trip with his family when his brother tried to get rid of him and pushed him into a room filled with slugs. Due to this incident, he developed a phobia on slugs. So he made the Roboslug to replace them with the original slugs. Then Eli plans to face Quentin using a giant robot they make using their Mecha beasts. Quentin has the advantage in the fight as he was using the roboslugs. The Shane gang's robot was losing all it's parts and collapsed. Eli and Quentin were about to start a duel when Quentin's brother and sister threw a bunch of slugs at him. He started running about in the place when Eli shot a Flopper slug named Noodles at him. Noodles saves him by ordering the slugs to save him from his robot when it was falling on him. He develops a liking on Noodles and resists his phobia. He was sent to jail when Dr. Blakk offered him an opportunity to join him and give his roboslugs for ghouling. Quentin accepts the opportunity.

Summary: Shinai, The unbeatable master of slug slinging had a fight in a hotel. The Shane gang were passing and Eli meets her.Trixie mentions that she is the unbeatable master. She then leaves the hotel. The very same night, the gang talk about her and want to get some training from her. Eli was very eager that he left early in the morning to her home. He was surprised to see a lot of slingers who wanted to get trained. She helds a competitions in which a majority slingers were disqualified. But they refuse to leave. So she performs the legendary fusion shot using her slugs, Sonikin and Inkdevil and throws them out. She held a tournament and whoever wins gets trained from her. Twist comes in a disguise. Twist and Eli go to the finals. An hour before the finals, Eli talks with her that Twist shouldn't get trained from her. She tells a flashback that Will Shane and Blakk came to her. She trains he one who wins in the duel. Will wins and gets trained. Blakk become enemy to Will and starts experiments with Ghouls. Will could've known the secrets of slugterra even without her help. She feels guilty that Blakk turned evil because of her. When Eli and Twist were about to duel, Blakk interferes with some soldiers, a bull mecha and a new gattling blaster. Sinai duel Blakk, Eli duels Twist and the gang duels the soldiers. When Twist is defeated, he flees but disguises as Blakk and fights with Shinai. She defeats him using the fusion shot and the disguise wears off. Blakk kills her by shooting a Boon Death (Ghouled Boon Doc) at her on the back. Eli asks help from his Boon Doc but it was of no use. Eli uses his blaster and defeats Blakk by performing a fusion shot with Burpy and Joules. Blakk leaves the place while the gang feel sad about her death. Even her slugs also go with her.

Summary: Eli and his gang have to stop a drill that is in an underwater cavern.

Summary: Danna uses the device she stole from the treasure chest to teleport from one place to another and becomes a thief. She steal things from everyone, even Trixie's camera. By mistake, she steals Blakk's blaster. So Blakk appoints a Gentleman to get his blaster and Danna alive.Gentleman is an experienced slinger who uses Geoshard slugs to crystallize his opponent. Knowing this, Eli tries to save her from the gentleman. The gang blackmails him to change the plan. When he confronts her he duels her. Blakk and Eli come later to the duel . Gentleman shoots her in such a way that she doesn't get crystallize completely. The crystallized Danna falls into a river. Eli saves her and escapes. She gets cured using Pronto's Slyren. Eli thinks that the device will be safe with Danna.

Summary: Lumino Cavern has been invaded by a swarm of Neurotox ghoul slugs that have created a toxic cloud that’s attacking the residents. The Shane Gang must brave an inescapable maze to locate Blite, the only man who can help them.

Summary: Eli and Kord have been trying to create a fusion shot which consists of two slugs being shot at the same time using both of their powers. In order to make it work, they’ll need to travel to Scrap Heap, a junk yard cavern protected by Boss Ember and his Scrap Force.