A rather contrived story is set in the Minnesota lake country and has to do with 15 year old Don Spicer, his police dog Frosty, and the mystery of his friend Grandpa Dan's lost grandson. First, Frosty a problem is that he was once a guide dog for the blind but was dismissed from duties after a shock from a fire made him unreliable. Don is determined to retrain him. Then, Grandpa Dan is overjoyed to have news of his grandson Jude. But when Jude arrives it is with a ""rancher"" with whom he has been living in Texas, and, as suspicious mount, he turns out to be posing as Jude in hopes of getting his inheritance. When the real grandson turns up, blind, there is a climactic forest gire in which Frost proves himself, Jude's guardians are unmasked and things are set right all the way around.