Low budget film noir with Helen Walker as an unfaithful wife who schemes have her rich husband (Brian Donlevy) murdered during a car trip. When her lover/accomplice fails to complete the kill and is consumed in the flames of a crash with a petrol truck, everyone assumes it is Donlevy's burned corpse at the scene of the accident.
While the concussed, amnesiac husband stumbles into a small town in Idaho to work as a mechanic for the tomboyish Ella Raines, Walker is busted by a smart Irish cop (Charles Coburn) and goes on trial for a murder that never happened.
Impact demonstrates how robust are the conventions of film noir. It's a reshuffling of noir archetypes and situations, made by a minor director and crew with a B standard cast. But it's still very entertaining, with plenty of atmosphere and strong performances.
Donlevy is fine as a schmuck that gets played for a sap, and Raines lifts the second half as the down to earth good girl who contrasts with Walker's glamorous femme fatale. Arthur Lubin was a lifelong director of support features, but he could turn out a pacy thriller and he handles the narrative well. Film noir rarely lets you down.