Sage is the younger sister of Murphy, and is the entomologist for Kim's fly fishing trips. She is living proof that nurture has nothing to do with how a dog behaves: Murphy is the perfect retriever, while Sage could not care less about fetching a tennis ball or duck.

Sage is mischievous, silly, and makes Kim laugh unless it is the middle of the night and Sage creeps on the bed trying to steal a pillow.