Twelve-year-old Slate Stephens and his friend Daphne McSweeney are enjoying their summer in Montana, riding their bikes, stopping for milkshakes and just generally having a good time when they read the news that the beloved governor's dog, a border collie named Cat, is missing. Is this part of a conspiracy? Is it a move by the governor's opponent to level the playing field for the next election? Has Cat been kidnapped? What about all the grizzlies roaming the National Park near them? Slate and Daphne take it upon themselves to find Cat, but can they do it before it's too late?