Dr. Blakk finds a way to make his ghouls stronger thanks to a special device. Hoping to find a counter-measure,the Shane Gang looks for Red Hook. Entering Quiet Lawn, they instead encounter Twist and Blakk's men. Eli enables his friends and slugs to escape, but gets captured by Twist and El Diablos Nacho. 

Dr. Blakk and the Darkbane once and for all. When Eli, Trixe, and Kord

arrive they find Blakk and his goons waiting outside. Eli charges in to

destroy the Terraportal but already finds it active and is forced to duel

Blakk one on one while Trixe and Kord duel everyone else outside. However

the gangs blasters can only handle MegaMorph energy before a cooldown and

suffer defeat due to Blakk and the Barkbane not having this handicap for

some reason.

Seen through the eyes of the slugs, the Shang Gang must liberate a cavern with the help of a new member of Eli's team a Blastipede slug named Rookie.

While his henchmen attempt to spring him from prison, Dr. Blakk tells Eli his life story and describes his rivalry with Will Shane. 

Mientras Ely y su equipo transportan al Dr. Blakk a la prisión de Estalagmita 17, Koro ha hecho una mejoras en las "mecas" haciéndolas mucho más rápidas. Pero Quentin se ha unido a Blakk y junto a sus secuaces intentarán liberarlo por todos los medios.

Los habitantes de una caverna solicitan la ayuda de Eli y su equipo por que un extraño mostruo, que ataca de noche, está absorbiendo la energía de todas las slugs. Nada, ni nadie, parece poder detener a este monstruo, invisible.

Durante una lucha Eli es golpeado por una slug rastreadora por CC al tiempo que huye con Eruptín enferma. Las slugs le dirigirán hasta la caverna del Clan de las Sombras, lugar en dónde podrá sanarla bajo la "Claraboya". Pero el Dr. Blakk le ha seguido el rastro y planea su destrucción

El Maestro del Juego engaña a Eli y a sus amigos con una falsa llamada de ayuda y les hace caer en una trampa y cada vez que usan una slug ésta es capturada por el Maestro al tiempo que aumenta su fuerza. ¿Cómo salir de esta pesadilla?

 Pronto and Burpy must save The Shane Gang from prison.

It's up to the Shane gang to help The King duel with Dr. Blakk to save his home cavern.

Kords' troll friends compete in the Slugball but when they are injured, it's up to the Shane gang to find out why the battle field is infested with high-tech traps, and come out victorious.

 Eli tries a fusion shot on Dr. Blakk's unstoppable train but he uses the wrong slugs and shorts out his gang's slugs. The Shadow Clan confront Eli and teach him how the Enigmo slug has the ability to allow the Slugslinger to see a slug's aura. Eli, learning more about the double barrel-fusion shot, confronts Blakk's Gattler and destroys his new Slugterrian Express train.

Nuestros amigos acaban en el fondo de una caverna profunda por culpa de Blakk pero allí descubren algo muy inquietante: una fuerza oscura, de los veneno oscuros, que amenaza a los seres de las sombras y a toda Slugterra, Eli decidirá ayudarles aún a costa de su propia vida.

 Eli quiere crear un arma que le ayude con la fusión de slugs y para ello necesita, entre otras cosas, una pieza que se localiza en el interior de un remodelador de aire, para poder enfrentarse a la poderosa arma de Blakk. Koro les conducirá hasta la chatarrería.

 Nuestros amigos se enfrentan a Escurridizo en Veta Lúmino y que Blakk quiere hacer suya. Pero las slugs neotox que arroja provocan una niebla que petrifica a aquel que la respira. Intentarán contenerla pero el tiempo juega en su contra y tan sólo Blite puede ayudarles.

 Dana es la ladrona que está detrás de todos los robos que se están produciendo en Slugterra. Pero su vida comienza a correr peligro cuando, tras robar al Dr. Blakk, éste contrata a Caballero para que acabe con ella.

Eli y sus amigos tendrán que ayudarla.

 Eli and his gang have to join forces with Captain Malvolio Drake to stop a drill that is in an underwater cavern.

 Eli y sus amigos conocen a Shannai, la Maestra Imbatible que busca a un discípulo para convertirlo en maestro. Pero el Doctor Blakk y Escurridizo harán acto de presencia para intentar acabar con la Maestra.

Tras un enfrentamiento con los esbirros del Dr. Blakk, las slugs de Eli se dirigen a casa solas. Al mismo tiempo, una caverna está siendo devastada por el enorme Zampa y Eli le retará a un duelo sin percatarse de que no tiene a sus slugs.

Tras un enfrentamiento con los esbirros del Dr. Blakk, las slugs de Eli se dirigen a casa solas. Al mismo tiempo, una caverna está siendo devastada por el enorme Zampa y Eli le retará a un duelo sin percatarse de que no tiene a sus slugs.

Gar, un cgarlatán de Slugterra, dice conocer el camino para llegar a la superficie terrestre. Eli, aterrado ante tal posibilidad, decidirá actuar por su cuenta sin contar nada a sus amigos. Pero éstos le demostrarán lo que significa la palabra "amistad".

Danna comes looking for treasure that she believes Will had hid from her father. Only the Forgesmelter can melt the chest. The gang search for the Forgesmelter in Magma Caverns. 

While watching a drive-in movie the Shane Gang get into a fight with the Hooligang, and in the heat of the battle they awaken an Ice Ogre which increases in size when angered. Eli surrenders the duel to avoid causing a cave in. Eli saves the Manager of the Theatre (a molenoid) who advices him to use the Slyren slug which can put the Ice ogres back to sleep.

Along with Twist, the Shane Gang plan to rob a train carrying the last of Dr. Blakk's Dark Water. They work out the plan and are trapped by Diablos Nacho. Kord realises that Twist works for Dr.Blakk and warns Eli. While in the fight, Twist traps Eli and duels him. He tells that he is an orphan because of Will Shane. 

Along with Twist, the Shane Gang plan to rob a train carrying the last of Dr. Blakk's Dark Water. They work out the plan and are trapped by Diablos Nacho. Kord realises that Twist works for Dr.Blakk and warns Eli. While in the fight, Twist traps Eli and duels him. He tells that he is an orphan because of Will Shane. When Eli has the advantage in the duel, he escapes. In the end, Dr.Blakk replaces El Diablos Nacho with Twist. 

Nuestros amigos acuden a un centro comercial para divertirse y hacer unas compras, pero cuando llegan ven que no hay gente sólo zombis. Con la ayuda de un vigilante de seguridad se enfrentarán a estos extraños seres y a Sábado, un secuaz que posee una slug criptogrifo. 

While riding through the mystifying Flumes, a river that flows beneath Slugterra, the Shane Gang runs into Pirate Captain Malvolio Drake. 

Trixie descubre dónde pueden encontrar a una rara slug que, además, se encuentra en peligro de extinción: la slug enigmo. Irá en su busca junto a Eli y sus amigos, pero no son los únicos que la buscan y tendrán que enfrentarse a un duro rival.

Pronto gets captured for spitting out gum in a part of town that it is illegal. So the gang tries to free Pronto, but to do that they need the help of a master trick shooter Mario .

The Shane gang interrupts an attack, caused by two of Dr. Blakk's employees Locke and Lode, on a shipment of Fandango slugs which are needed to revive Bullseye Cavern after the native slugs fled out of the place due to dark water.

Eli and the gang enter the Deadweed cavern, an old abandoned mine shaft for Frightgeist slugs. They get ambushed by the miners who turned into ghosts by Dark Water. They discover that Blakk uses Dark Water to turn normal slugs into ghouls. 

The gang is out hunting a very speedy slug (Zipper Slug). During the chase their Mechas malfunction. Back at the hideout Kord tries to figure out what the issue is but he can't. He thinks it might have something to do with the new upgrades he got from his friends back at the forge (a factory of Mecha Beasts) so they head there to have it checked out. 

After watching a commercial for the Slugterra "Slug Run" Eli immediately wants to join it despite Kord's warning that the race is for experienced Mecha beast riders.

The gang decides to sign up for a weekend camp called Club slug in an effort to learn a number of new moves without having to do all of the hard work. 

 The gang was looking for Frostcrawler slugs. Due to Pronto's mistake, all the slugs fall and reach velocity. All the slugs transforming at the same time creates an ice hazard. The gang escapes and a Frostcrawler follows Eli.

He names it Chiller. When escaping, Eli's blaster is destroyed. Kord says that only Red Hook can fix his blaster. So they go to Quiet Lawn Cavern, home of Red Hook. The Cavern is located under a bunch of Grenuker slugs

which is a problem for the Cavern people. The Cavern is threatened but Billy, Shorty, and Glasses who are members of the Hooligang, the official employees of Dr. Blakk. Eli defeats Billy in a Trick Shot Competition. Billy

only has a Boon Doc slug who doesn't know what it does. He thinks it useless and releases it but Eli recruits it into his team and names it Doc. Billy seeks Dr. Blakk for Ghoul slugs and returns with vengeance. Mean while, Eli

gets a new blaster from Red Hook and faces the Hooligang. In the battle, Eli discovers that Boon Doc slugs have strong healing powers and can purify Ghoul slugs.

The gang runs into a slinger with ghoul slugs and are defeated by him. They return home to a destroyed hideout. In order to replace all the gear destroyed at the hideout and in the battle against the slinger, they have to get new gear and a few upgrades. To buy all the gear, Eli has to trade Joules. On the way back home, Eli decides to get his slug back and goes to the shop.

Eli Shane wins all the rounds in the tournament and along the way gets new slugs. He is offered a chance to join Dr. Thaddeus Blakk, an evil scientist who works on ghouling slugs. 

Will Shane is the Beacon of Justice in Slugterra. He disappears when Dr. Blakk uses a Tempesto (Ghouled Tormato) in a duel. Before Will disappears he tells his slug, Burpy (an Infurnus slug), to find his son Eli and give him a letter. When Eli turns 15 years old he and Burpy go to Slugterra for the first time. He gets gear, a blaster and a Mecha Beast which he names Lucky from his father's hideout and meets Pronto (a proud and knowledgeable molenoid tracker). Later he meets Beatrice "Trixie" Sting who saves him from a slug slinger.