I Love a Mystery Collection

In San Francisco, detective partners Jack Packard and Doc Long are hired by socialite Jefferson Monk who believes someone is following him with the aim to kill him.

A San Francisco airplane bound for South America crashes, and among the scorched debris is found a shrunken native human head, neatly packaged. The perplexed police contact a local anthropology museum about this unclaimed piece of grisly baggage, where they intersect with Jack and Doc, two private eyes, called there to meet a mysterious woman who had a case for them and wanted to meet in private.

"The Unknown" was the final entry in Columbia’s I Love A Mystery series. A woman hires two detectives to keep her alive long enough to claim her inheritance.