Following his father's death, 15-year-old Eli Shane embraces his destiny to follow in his dad's footsteps to a secret, subterranean world called Slugterra where he is determined to be the greatest Slugslinging hero of them all!

The time has come for Eli and the Shane Gang to take their new friend Junjie home to the strange and beautiful Eastern Caverns. But when they arrive, they are shocked to find a world darker and more dangerous than Junjie remembers.