When Gravelmuck Elementary's cleaning slimes escape and destroy the schoolyard with their acidic ooze, all claws and tails point to Mr. Snag, the school's caretaker, as the culprit. Determined to clear Mr. Snag's name, Tank and Fizz dive into the case, only to discover that the goop under Rockfall Mountain runs deep. The detective duo must outwit their eight-legged principal and survive an ancient war between high-tech janitors and spell-slinging...