Too Late for Tears.
"One night on a lonely highway, a speeding car tosses a satchel of money, meant for somebody else, into Jane and Alan Palmer's back seat. Alan wants to turn it over to the police, but Jane, with luxury within her reach, persuades him to hang onto it "for a while." Soon, the Palmers are traced by one Danny Fuller, a sleazy character who claims the money is his. To hang onto it, Jane will need all the qualities of an ultimate femme fatale...and does she ever have them!"
Aside from the fact that Lizabeth Scott looks like a man in a dress, the plot has more twists and turns than a rollercoaster.