Fraser returns from vacation to a blazing apartment and a new partner, Stanley Ray Kowalski. After trashing half of Canada in pursuit of a felonious litterer, Fraser is contacted by Ray, who says he can't pick the Mountie up when he arrives back in Chicago. When Fraser gets home, he finds his apartment building gone: all that remains is a pile of blackened rubble, the result of a 'performance arsonist.' Worse yet, when he arrives at the precinct, he finds a stranger masquerading as Ray Vecchio and, curiously, no one seems to realize this except Fraser. Fraser decides to go along with this ruse, all the while utilizing a variety of detection techniques (fingerprints, dental imprints, etc.) as he tries to unravel who the mysterious person is who now answers to the name Ray Vecchio. Along the way, Ray's house is torched (Fraser rescues both Frannie and her perpetually unemployed brother-in-law, Tony, but the goldfish befalls a foul fate when Diefenbaker eats him). Fraser finds more evide