Boris Karloff headlines an ensemble cast in this tepid whodunit set on an island military research base.

The film opens with Private Pratt smuggling his new bride Sally onto the base in his duffel bag. In scurrying from tent to tent trying to consummate their marriage, they duck into a warehouse where they discover a dead body bound to a post and speared with a bayonet.

Sally screams, alerting the patrolling guards and setting the mystery plot in motion. We meet a plethora of suspects, including Karloff, who plays the base’s construction manager. Desperate for help, the commanding colonel calls in an old friend, an intelligence officer played by Cy Kendall.

Kendall has a history with Karloff and fingers him for the murder. Unlike the rest of the cast, who come across as bland at best, Kendall delivers a performance oozing self-righteous sleaze. You can see the sanctimonious glee twinkle in his eyes as he sucker-punches Karloff for not confessing, and behind said twinkle a rising fury at Karloff’s obstinance.

Opposite Kendall, Karloff gets some big pleading scenes, but the nonexistent emotional stakes render them inert. The film trades on our familiarity with Karloff playing horror villains instead of providing his character with agency and substance. Unlike Kendall, who shows his character’s corruption through his actions, Karloff can only tell, reacting with expository dialog and stale denials like, “I did come here to get him, but somebody beat me to it!” and then, “I haven’t admitted it, I’ve nothing to do with it!”

Meanwhile, Sally interjects herself into the proceedings, pointing out obvious clues that lead us to the killer’s identity long before the cast.

Most of the film unfolds in the uninspired warehouse where Pratt and Sally discover the body. Swarms of people come and go. This strains credibility, not just because it’s a live crime scene, but because early on they discover a booby trapped grenade. Then later, they lock a suspect in the warehouse’s back-room, which holds spare sidearms. Did the base not have a brig or at least a closet?

Besides betraying the film’s meager budget, it makes the proceedings feel like a transplanted stage production. Everyone stands around a single set delivering reams of dialogue. The script proffers no measure of intrigue or suspense to compensate for the staid action.

The film’s best scene occurs during a flashback explaining Karloff’s backstory. In Haiti, jungle drums beat as Karloff awakens from a drunken stupor. Inky shadows lend the tropical hut an ominous atmosphere as Karloff stumbles out of his bedroom and discovers his wife and friend up to no good.

This proves the film’s lone moment of genuine atmosphere and tension. The rest lands between one-joke comedy (Pratt and Sally trying to have their honeymoon) and talky melodrama (everything else) making for a tedious experience, even at only an hour long.

Karloff completists may appreciate the relative novelty of this non-horror entry, but others should steer clear.