When his mother brings home a guinea pig instead of the dog he has always wanted, fifth-grader Rufus is not happy--until the rodent starts acting exactly like a dog.

Hissy, a sleep-deprived British shorthair in the extremely noisy Fitz household, recounts his frustrating day trying to find a place to sleep where people--particularly an annoying three-year-old human--will not bother him.

Because Claudine thinks Santa is rude, she tries to keep him from coming down her chimney by getting on his naughty list.