A famous fashion designer is murdered, and the police are baffled. An amateur criminologist, whose father is the police inspector in charge of the case, decides to solve it himself.

At a New Year's Eve party where Guy Lombardo (as himself, albeit about 30 years older than he would have been at the time), Inspector Queen finds blood on a drawing-room floor outside a phone booth, and a knife wedged in the phone booth's door. When Inspector Queen pulls the knife out and opens the door, a body tumbles out. Inspector Queen then finds the phone itself dangling, picks it up and hears a bewildered stranger on the other end. The dead man, a wealthy industrialist, had telephoned the stranger but couldn't talk because the knife had severed his vocal cords. The industrialist had been unable to crawl out of the booth because the knife jammed it shut. There are a plethora of suspects whom the industrialist had insulted just before his death.

Stephanie Kendrick, a wealthy fountain pen heiress, is found dead on the front lawn of her mansion. Prior to her death she was reading Ellery's book "The Adventure of the Lover's Leap" and it seems that she acted out a passage in the book which leads to her to jump from her bedroom balcony. Inspector Queen thinks her death is suicide, but Ellery seems to have other thoughts when a Technical Print Man finds a small chard of glass on the balcony. Later during the questioning of suspects, Simon Brimmer arrives at the Kendrick mansion and, in his typical pompous fashion, offers his help to Inspector Queen solve what he concludes to be a murder. Ultimately, Brimmer brings the cast together at the conclusion to disclose the guilty party, but Ellery finds the exact time to speak up and reveal the killer's identity.

Ellery and his father are on a fishing vacation 200 miles from New York City when they are informed of the murder of Eben Wright. He was a rich manufacturer of galoshes, killed by a blow to the head from a valuable Chinese Temple Dog made of solid gold and encrusted with gemstones. Although Inspector Queen would rather catch fish instead of a murderer, Ellery is intrigued enough to sort through the evidence and eventually unhands a dying clue which helps him to pin down Eben's killer.

Ellery picks the wrong man to mess with when he becomes irate with a comic-book editor who had dictated a series of books depicting Ellery as a two-fisted brawling sleuth. The following night, as the editor is working alone in his office, a custodian hears three gunshots. The editor is found slumped over a panel he was reworking, and with a blue pencil he has crossed through Ellery's dialog balloon. If that wasn't incriminating enough, newspaper reporter Frank Flannigan finds the murder weapon, a revolver, in Ellery's fish tank, where the water has long since washed off all prints. Ellery must clear himself in a big hurry before he goes to trial.

A newspaper publisher gets onto the express elevator on the way to his 12th-floor office. But when the elevator, a new model with push buttons for each floor (the operator pushed the top-floor button) gets to the top floor, the publisher is nowhere to be found. The elevator closes and goes down. To the horror of staffers on two lower floors, the elevator opens at each floor to reveal the publisher, who's dead from a gunshot wound. The publisher himself had pushed the buttons for the two floors before he died, implicating someone -- but who?

Miss Aggie is the central character on an immensely popular radio soap opera. The actress playing her collapses in the recording studio, and it's revealed that the water jug she drank from was poisoned. The actress survives and seems to be recovering. Her producers try to stifle the police investigation into the crime, claiming the actress poisoned herself to garner the sympathy vote from fans -- her contract was expiring, and she was about to be written out of the show ("Pow! Double pneumonia and she's off the air for a month and when she comes back nobody will remember what she sounded like."), Unfortunately, the killer comes back -- this time with a gun -- and Miss Aggie's departure is indeed permanent. When a hospital attendant is arrested for robbing the body of the actress's prize bracelet, it's revealed that she had left a dying clue for Ellery.

At a book signing Ellery is introduced to Colonel Alec Nivin who is signing his recent publication "Memoirs of a Spy" on the book's first day of sale. The book is a character assassination of various British, French, and Russian operatives who are now living in the United States after WWII. Later that evening when one of the exposed operatives kills Nivin, Ellery and Inspector Queen must sort through Nivin's files to find the killer. As the list of suspects keeps growing, it isn't till Ellery realizes that the killer could only have bought Nivin's book on the day of the murder at the Gotham Book Store since Ellery was there and he bought the last copy of the book.

A fun-loving theatrical producer, who dresses as the Mad Hatter, invites Ellery up to his mansion for a weekend of working out how to adapt one of Ellery's works for the stage. But the producer disappears shortly thereafter and is presumed murdered. Over the rest of the hour, a series of clues are delivered by pranksters' means. The idea is to try to get the killer to implicate himself or herself.

George Burns (who receives "special appearance by" billing in the end titles) plays Sam Packer, a wisecracking theatrical producer who appears in his own funeral, via a film he made shortly before his demise from an apparent heart attack. Packer's monologue, in true Burns style, is a riff on his own death and how he believed he would be murdered. It turns out the Packer was indeed poisoned in the dressing room of a stripper queen. But she didn't have enough clothes on to smuggle the poison into the room, did she? In fact, nobody seemed to be able to get into the room with the poison. As Ellery says just before revealing the killer: "You'll know who once you figure out how."

A museum benefactor is found dead in the museum. The autopsy indicates he died of a heart attack. The question then is: did he have help in dying? The benefactor was let into the museum by somebody and couldn't reach his nitroglycerin medicine, indicating that whoever let him in also intimidated him. The plot thickens further when an Egyptologist shows up and claims that the piece, a pharaoh's tomb, was stolen from Egypt and vows that a curse has been laid upon the tomb to haunt anyone who dares rob it. John Larroquette has a tiny bit part as a hotel doorman; several major characters, lacking "clout," are relegated to the "co-starring" end credits.

Edgar Manning, a mystery writer, wins the annual Blunt Instrument Award for his year's work and goes to pick it up at a party. Ellery, who was Edgar's rival for the award, is sidelined because of a nasty cold. So Edgar gleefully phones Ellery and gives a blow-by-blow description of the award ceremony (including describing the trophy) as he leans back in his easy chair. But the phone call is interrupted by a sickening thud. Ellery calls out to Edgar but gets no response. Cut back to Edgar, who's now face down on his desk. His skull was shattered by ... The Blunt Instrument, the trophy itself.

Letting a fine wine "breathe" proves to be a deadly mistake for the wine's owner, who leaves it unattended for a killer to slip a dollop of colorless, odorless and tasteless poison into it. The vintner, who's hosting a party upstairs, comes back only to collapse. He tries to implicate the killer but breaks the wine cellar's only pencil, so he crawls to a wine rack and grabs a bottle, smashing it on the floor. The shattered bottle bears the label Black Falcon, indicating it was tied to World War One. But how?

During a practice bout, a lucky shot knocks a champion boxer unconscious. He revives enough to sip some water from his manager's "swill bottle," then falls comatose and is soon pronounced dead. An autopsy reveals he was poisoned, and the "swill bottle" was loaded with poison. The manager is strongly implicated, but so is the opponent.

A famous inventor suddenly withdraws from the world and starts holing up in his shed, playing incessantly with his toy trains. So why would someone kill him? A clue at the beginning of the show: before the inventor answers the knock of his killer, he hides some secret formulas in a secret-compartment desk drawer.

A man on trial for murder claims that the victim was shot through a window from a fire escape, and that he fired at the killer. The defendant's lawyer claims that he can bring in a witness, a woman who was beaten up by the victim. But the woman can't be found. When she's finally tracked down, Inspector Queen, Ellery and Frank Flannigan hear a gunshot from outside her window, break down the door and find the woman lying unconscious -- shot from the fire escape.

Soemone goes to an awful lot of trouble to make the murder of a wealthy man look like a ritualistic killing, hanging his corpse from a Cersis tree (aka a Judas tree, after the one Judas Iscariot supposedly hanged himself from) and adorning it with branches. When the wealthy man is found to be far less wealthy than thought (he had given everything away except a huge life insurance policy), suspicion turns to his wife, who already has a boyfriend on the side.

An actor playing Ellery Queen in a motion picture is supposed to be "shot" on camera, then jump up and nab the woman who shot him, exclaiming "Bulletproof vest!" The rehearsal, with blanks, goes fine. But the ensuing "take" with the same gun finds it loaded with real bullets, and the actor drops dead. The film crew tries to carry on, and soon a stunt man is killed when the car he was driving is rigged to wipe out before he was ready. Are the two murders linked -- and how?

A society matron is stabbed to death while examining a painting she has purchased at auction. She had started to scrape off the painting to get at another painting underneath, and had uncovered the artist's signature -- "Lazar," a key figure in an unsolved (and heinous) murder in Paris 25 years earlier. When the rest of the painting is revealed, it's a portrait of the dead woman herself. Investigation reveals that the woman was in Paris at the time of the murder and may well have been the killer, but she subsequently completely lost her memory. Somebody didn't want her to regain it.

A famous crooner who's also a cutthroat record producer is doing a radio interview when a songwriter breaks into the studio and accuses the singer of stealing his song, waving a demo record around as proof. The singer smashes the disc and storms out. The interviewer hurriedly cues up some records to cover the dead air. While everybody in the radio station searches for the singer, someone finds him in the music library and shoots him. The singer is found clutching a recording of "Danny Boy," which implicates the songwriter (whose name is Danny). But is it a dying clue or a red herring?

A mobster survives a bombing attempt and plays dead, hiding out in a hotel room with two police guards. But the mobster is found dead anyway, of poison. A furious crusading District Attorney accuses Inspector Queen and the two guards (including Velie) of serving up poisoned chewing gum, the only thing the mobster had to dine on. Ellery thinks this unlikely because nobody opened the packet except the mobster, and starts looking for other ways the poison could have been administered.

A Madison Avenue advertising executive wants to make newspaper columnist Frank Flanagan a TV star by setting him up with a variety show. But then the executive is found murdered in his private bathroom, stabbed in the back. The killer had to be someone who knew the executive's meticulous habits. The plans for the TV show go forward and Ellery takes an inside look at the advertising industry to determine how the killer could have slipped in and out undetected.

An elderly amateur criminologist finally figures out how a five-year-old "locked-room" murder was committed, and is murdered by the killer before he can alert Inspector Queen. Ellery takes up the challenge himself. The criminologist had first implicated an airline pilot, because he was flying the plane where the murder was committed and had the opportunity to toss the murder weapon out the window. Nobody else seems to have been able to get rid of the weapon, but Ellery finds that the murder victim had stolen someone else's invention, and that the murderer may have invented the weapon as well.