"It's summer vacation, and in this third in the light-reading Guinea Dog series, Rufus' and Murph's families are taking their traditional trip to the lake, unusual guinea pigs included. Rufus is excited to share the experience with Fido, his guinea 'dog' from Petopia, the store that disappeared as fast as it popped up. Unfortunately, his mom has also invited the families of Rufus' nemesis, Dmitri, and a girl, Lurena. At least Lurena will be bringing Fido's daughter, the guinea 'squirrel.' Let the games begin! While swimming, Rufus nearly drowns Fido, who is only resuscitated after another camper, Pablo, offers advice. He joins their circle but, oddly, won't swim. Murph saves Rufus from his dad's grilled mushrooms ('Seriously?') with a well-timed hot dog. Lurena turns out to be a loyal ally. Bully Dmitri's behavior becomes so bad that even even-tempered Murph notices. Rufus narrates it all with his by-now-familiar, entertaining mix of preteen self-conscious self-involvement and dawning maturity. Murph and Dmitri are a bit one-dimensional, but in them, readers will easily recognize kids they love and love to hate, respectively. Pablo offers a nice counterpoint to Rufus' hesitancy when he boldly confronts his self-imposed limits when pushed. Why? Because Petopia has popped up again, and Pablo is now the proud owner of a guinea 'otter,' meaning Pablo must swim. Youngsters will eagerly jump in for another fast, fun read." (Kirkus Reviews)