The benefactor of the Stack Memorial Hospital dies after an operation. Ellery Queen investigates when it is revealed the cause of death was murder by strangulation.
| Actor | Role |
|---|---|
 Ralph BellamyEllery Queen | Ellery Queen |
 Margaret LindsayNikki Porter | Nikki Porter |
 Charley GrapewinInsp. Queen | Insp. Queen |
 Mona BarrieNurse Marian Tracy | Nurse Marian Tracy |
| PPaul HurstPage | Page |
 James BurkeSgt. Velie | Sgt. Velie |
 Leon AmesJohn Stack | John Stack |
 George ZuccoDr. Edwin L. Jannery | Dr. Edwin L. Jannery |
 Blanche YurkaMrs. Augusta Stack | Mrs. Augusta Stack |
 Charlotte WyntersMiss Fox | Miss Fox |
 Tom DuganLou Thomas | Lou Thomas |
 Olin HowlandDr. Williams | Dr. Williams |
 Dennis MooreDr. Dunn | Dr. Dunn |
 Jean FenwickAlice Stack | Alice Stack |
 Pierre WatkinCrothers | Crothers |
 Byron FoulgerHospital Orderly (uncredited) | Hospital Orderly (uncredited) |