Colleen Barker, Eliot's neighbor, asks Eliot to puppysit her nephew Pomeroy. Eliot quickly finds out that the previously sweet looking pup turns out to be a paw-ful. However, Pomeroy becomes the inspiration for Eliot's next Ace Hart adventure. Puppy-Face Felson, a cute but notorious criminal dog, sets up a plot with Bugsy Vile and his gang to steal Zsa Zsa Gbark's Hope on a Rope Diamond. The plan goes awry when Puppyface is put into Ace's custody until his 'parents' are found.