Set in 1890, Dark Intruder opens with a woman being slain on the foggy streets of San Francisco. Her murder turns out to be one in a series of killings that have baffled the police. The case has also caught the eye of Brett Kingsford (Leslie Nielsen), a “chronic dabbler” who had aided the authorities in previous cases. Brett, a rich dapper gentleman with an eye for the ladies, has developed an interest in the occult. His family’s crest reads: “Omnia Exeunt in Mysterium”…or “Everything ends in mystery.”
As Brett delves into the case, he learns that the killings are ritualistic ones tied to a Sumerian god representing the essence of evil. To give away any more of the surprisingly complex (and, at times Lovecraftian) plot would be to spoil the fun.
Dark Intruder was originally made for television and intended as the pilot for a prospective TV series called Dark Cloak. However, it was released to theaters instead and a television series never materialized. One suspects that the tale was a little too gruesome for network television in the 1960s. It may also be that Nielsen, though he tries hard, was a little lightweight to to take on the role on a weekly basis.
I suspect that Dark Intruder would have faded quickly a TV series. Its formula could have grown stale on a weekly basis, as it did for The Night Stalker in the 1970s. But, as a limited film series, it could have been most diverting as evidenced by this closing exchange:
BRETT: Ah, Nicola, if only the rest of the world knew what we know.
NICOLA: If they did, sir, nobody would get a decent night’s sleep.