S1E39: Light as Day

Dr. Blakk has succeeded in creating a gap in the magical slug-energy barrier that protects Slugterra, opening the way for the evil Darkbane to tunnel their way up from the Dark Caverns. Eli and the Shane gang must stop this at any cost. Now armed with a selection of upgraded slugs, blasters and armor, they take the battle to Dr. Blakk's front door. While his team slugs it out against Dr. Blakk's minions, Eli takes on Blakk himself once and for all!