Letting a fine wine "breathe" proves deadly for the wine's owner Nick Kingston, who leaves it unattended for a killer to poison 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 champion boxer Kid Hogan 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 Joe Simpson.
Famous inventor Lamont Franklin 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.
Linville Hagen, on trial for murder, claims that the victim Nick Danello was shot through a window from a fire escape, and that Hagen fired at the killer. The defendant's lawyer Leo Campbell 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 makes the murder of wealthy George Sherman 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 George 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 Paulette, who already has a boyfriend on the side.
Gil Mallory, 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 Mallory drops dead. The film crew tries to carry on, and soon stunt man Mike Hewitt is killed when the car he was driving is rigged to wipe out before he was ready. Are the two murders linked -- and how?
Society matron Lilliam McGraw is stabbed to death while examining a painting she 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 have been the killer, but she lost her memory. Somebody didn't want her to regain it.
Famous crooner and cutthroat record producer Alvin Winer is doing a radio interview when songwriter Danny Murphy breaks into the studio and angrily accuses the singer of stealing his song. Danny threatens Alvin, then storms out with several others in pursuit. Alvin is soon found in the music library, dead and clutching a recording of "Danny Boy," which would seem to implicate Murphy. But is it a dying clue or a red herring?
Mobster Ralph Caesar survives a bombing attempt and plays dead, hiding out in a hotel room with two police guards. But he is found dead anyway, of poison. Furious crusading District Attorney Erwin Murphy accuses Inspector Queen and the two guards (including Velie) of serving poisoned chewing gum, the only thing the mobster had to dine on. Ellery thinks this unlikely because nobody opened the packet except Caeser, and starts looking for other ways the poison could have been administered.
Madison Avenue advertising executive James Bevin Long wants to make newspaper columnist Frank Flanagan a TV star by setting him up with a variety show. But then Long is murdered in his private bathroom, stabbed in the back. The killer had to be someone who knew Long'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 ...