Life has settled down for Slobbers, the hero Saint Bernard, after he and his human friends saved the little town of Serenity from invading giant snails. He misses his old home and his people, but he's happy living in the woods with Cole Black, the Lost Boy of Serenity.

But things don't stay quiet for long. Slobbers and Cole discover criminal activity in their woods, endangering both people and animals. It's time to get the slime-and-crime-busting gang back together. With the help of Bud, Sis, Deon, Lin, and their families, they set out to hunt down the evil doers. An adventure fraught with danger ensues.

Who are the villains? Is there more than one? Layers of sinister secrets begin to bubble to the surface, and it's up to Slobbers to prod his super crew of sleuths in the right direction to discover just who the villains are and put an end to their evil doings.

The heart and soul of the town is at risk.

Once again, it's up to Slobbers, a mere Saint Bernard puppy, to bring the serene back to Serenity.