Too Late for Tears

One night on a dark and lonely highway, a stranger from a speeding car tosses a bag full of cash, meant for somebody else, into Jane and Alan Palmer's back seat. Alan (Arthur Kennedy) wants to turn it over to the cops, but Jane (Lizbeth Scott) has other avaricious ideas. Lots of them.
Soon, the Palmers are tracked down by Danny Fuller (Dan Duryea), a sleazy operator who claims the money is his. To hang onto the loot, Jane will need to commit every sin in the book. And like a classic femme fatale, she's more than willing to do it. (official distributor synopsis)