The Mutts are a pack of stray dogs. They are to be featured in a future chapter of The Magnificent Journey of Lewis.
Not much is known about The Mutts. Each dog in the pack is a mutt (with the exception of one), hence the title.
- Hugo: The "alpha dog" of The Mutts. He is a cross between a St. Bernard and an English Mastiff. Mate to Cecelia.
- Cecelia: Hugo's mate, and a purebred Golden Retriever. Cecelia was a show dog, with the registered name "Cecelia's Breakin' My Heart." When her debut at a dog show became a major disaster, Cecelia's owners kicked her out. Hungry and alone, Cecelia eventually came across The Mutts. Nana nursed her back to health, and soon, Hugo fell in love with her. Cecelia is sometimes referred to as "Cee-Cee."
- Nana: A Great Dane crossbreed. Nana has had many litters of pups in her life, and after her last litter at the age of seven, she's become a surrogate mother to abandoned and orphaned pups, among them Barry. At the age of nine, Nana is the oldest dog in the pack.
- Zip, Zee, and Zah: Three Bassett hound crossbred brothers. All have the tendency to speak at the same time. They are usually referred to as "The Z Three."
- Boots: It is not known what breeds are in Boots's bloodline. She is a gray female with black legs. She is about the same size as a Labrador Retriever.
- Digby: A Dalmatian/Greyhound mix. Digby is very fast and very hyper. As a pup, he was orphaned when his parents were captured by dogcatchers, and Nana was the one who took care of him. He has a small crush on Brianna.
- Danny Boy: The youngest member of the pack, Danny Boy is a red Catahoula bulldog. No one knows who his parents were, or what happened to them. Just like with Digby, Nana has become Danny Boy's surrogate mother. Danny Boy is often referred to as "D.B."