Dr. Morelle marches on

Paula Webb visits Doctor Morelle with a startling confession. Believing that her former lover, nightclub owner Max Powers, had caused her sister's death, she shot him dead. A convincing story: Doctor Morelle and Miss Frayle were present outside the club when the police discovered Powers' dead body within. However, a suicide note is discovered - sufficient reason for the Doctor to suspect that Powers' death isn't what it seems - and to decide the case worthy of his legendary investigative talents ...