In post-war Los Angeles, Joe, a World War II veteran, returns home hoping to leave behind the horrors he experienced on the front. Upon reuniting with his wife, he discovers that she has fallen into a world of infidelities and vices. After a heated argument, Joe leaves, and that same night, his wife is found dead in their apartment, her body adorned with a strange bouquet of blue dahlias.
With the police on the trail of the killer, Joe becomes the prime suspect due to his tumultuous life and the circumstances surrounding his arrival that night. Determined to prove his innocence, he teams up with an old friend, an attractive and shrewd woman who will help him uncover the truth behind the crime. As they delve into a dark labyrinth of deceit and secrets, they encounter dangerous and twisted characters who seem to have their own agendas.
Amidst the investigation, Joe grapples with his inner demons, and the complex relationship he has with his partner leads him to question trust and betrayal. With each revelation, the tension escalates and everything becomes more complicated, culminating in an unexpected climax that reveals not only the truth about the murder but also the fragility of human relationships. In the end, the path to redemption will be as dark as the mystery they are trying to solve.