"Just when Eli Shane thinks Slugterra is safe after defeating Dr. Blakk, a new danger emerges from the dark edges of the 99 caverns. A mysterious Dark Slinger named 'The Goon' arrives, possessing a Ghoul slug that can control minds. Unlike any enemy they have faced before, The Goon is faster and stronger. Eli and the Shane Gang must master their skills and protect the caverns from this terrifying new threat before it enslaves everyone."
