Ken Morton (Robert Ryan) is a long time bank employee who has planned the perfect robbery from the bank he works at.
It does include working late at night, killing the guard and hiding himself in the bank vault.
However his ingenious plan to mailing the stolen money to himself causes issues.
The cop suspects him and getting hold of the envelope is not so easy.
An efficient thriller, Ryan gets more intense as the drama goes on.
You just know that Ken will never get away with it. He also wrongly assumed that he would never be a suspect.