The film opens early in the twentieth century, at an English country mansion with the apparent murder of Lord and Lady Morley in their car by a figure in a black cape.

Planning to kill the detectives and escape the mansion, she falls backward into a flower bed while retreating, where she is grabbed by the shadowy figure, who has been hiding in the dirt.

Morley had escaped the car crash and gathered the staff to gain their help in a plan to get the heiress to confess to the murder of his wife and the attempt on his own life.

Morley remained "dead" (in hiding) as part of the plan, writing the letter to Scotland Yard in order to request Winship and Tart as investigators, presumably because of their incompetence.

[5] The Private Eyes earned $12 million in rentals during its initial release, and became the highest-grossing film made at New World Pictures under Roger Corman.