The Great Detective was inspired by exploits of John Wilson Murray, Canada's first government-appointed detective, set in the latter part of the Victorian era. The leading character Inspector Alistair Cameron, played by Douglas Campbell, was a fictional counterpart of Murray. Inspector Cameron was ably assisted by his friend, forensic scientist Dr. Chisholm, played by Sandy Webster. Also giving Cameron a hand were his bodyguard Sgt. Striker (James Dugan); Willie (Roy Wordsworth), an ex-convict with underworld connections; Prudence (Tracy Brett), Cameron's young niece; and Mrs. Lutz (Kay Hawtrey) his housekeeper.