A pretty Chinese woman, seeking help from San Francisco detective James Lee Wong, is killed by a poisoned dart in his front hall, having time only to scrawl "Captain J" on a sheet of paper. She proves to be Princess Lin Hwa, on a secret military mission for Chinese forces fighting the Japanese invasion. Mr. Wong finds two captains with the intial J in the case, neither being quite what he seems; there's fog on the waterfront and someone still has that poison-dart gun...
Boris Karloff
Mr. James Lee Wong
Marjorie Reynolds
Roberta 'Bobbie' Logan
Grant Withers
Police Capt. Bill Street
Huntley Gordon
Mr. Davidson
George Lynn
Capt. Guy Jackson
William Royle
Capt. Jaime
James Flavin
Police Sgt. Jerry
Lotus Long
Princess Lin Hwa
