Detective Ellery Queen has to solve a series of murders where the victims were killed in numerically descending ages, the male victims were strangled with blue cords and the female victims with pink ones.
| Actor | Role |
|---|---|
 Peter LawfordEllery Queen | Ellery Queen |
 Harry MorganInsp. Richard Queen | Insp. Richard Queen |
 E.G. MarshallDr. Cazalis | Dr. Cazalis |
 Skye AubreyChristy | Christy |
 Stefanie PowersCeleste | Celeste |
 Coleen GrayMrs. Cazalis | Mrs. Cazalis |
| MMorgan SternePolice Commissioner | Police Commissioner |
 Bill ZuckertSgt. Velie | Sgt. Velie |
 Bob HastingsHal Hunter | Hal Hunter |
 Than WyennRegistrar | Registrar |
 Buddy LesterPoliceman | Policeman |
 William LuckingLt. Summers | Lt. Summers |
 Pat DelaneyMiss Price | Miss Price |
 Billy SandsAdrian Abbott | Adrian Abbott |
 Tim HerbertNot listed | Not listed |
 Robin RaymondNot listed | Not listed |