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 wizards. Can Tank and Fizz find the real monsters behind the slime stampede in time to clear Mr. Snag's name? The Case of the Slime Stampede is the first book in the Tank & Fizz mystery series about two crime-solving monsters living under a mountain.

When their school bus veers off course while taking the kids from Gravelmuck Elementary on a field trip, monster detectives Tank and Fizz witness a crime that brings them snout to snout with Rockfall Mountain's oldest monster, the ancient dragon Firebane Drakeclaw. Thieves have stolen the Crown of Peace, which keeps the monster clans of the Dark Depths from fighting, and Tank and Fizz saw the whole thing. Now the detectives must track down the thieves and find the crown or their whole class will become dinner for one very hungry dragon! The Case of Firebane's Folly is the fourth book in the Tank & Fizz series about two crime-solving monsters living under a mountain, following The Case of the Slime Stampede, The Case of the Battling Bots and The Case of the Missing Mage .

When valuable cargo ships vanish from Rockfall Mountain's busiest port, crime-fighting goblin detective Fizz Marlow and his troll sleuthing partner, Tank Wrenchlin, know Detective Hordish is going to need their help (whether he wants it or not). But it's Tank's mom, the harbor master who is really feeling the heat. It's her responsibility to keep the harbor safe, and the lost ships quickly cost her her job. Determined to help, Tank, Fizz and their wizard pal, Aleetha, dive into this new mystery, only to get tangled up with a terror from below that takes the detectives far from home and puts them snout-to-snout with a band of vicious kobold pirates. The Case of the Tentacle Terror is the fifth book in the Tank & Fizz series about two crime-solving monsters living under a mountain.