Tom Conway is a private detective (and yes his character name is also Tom Conway) is employed to investigate the theft of jewels in the fashion industry.
Eventually, Conway is removed from the case but the death of a woman who said she had information for him keeps him interested, though that isn't the only death and the red herrings come thick and fast.
It isn't a bad film but a bit tired and lack lustre, a bit like Britain in the post-war period really. Tom Conway has played a similar role to this many times and does pretty well with it - his presence and charm being the highlight of the film - as you would expect!