The Gwen Chalmers poisoning begins with an ordinary gift and turns a courtyard gathering into a medical emergency. Gwen eats chocolates from a box delivered through the mail, then collapses in front of Mrs Bortz and nearby residents. The Three Investigators identify a suspicious odor on a fallen piece of candy, and the later revelation that John Murphy sent the chocolates to keep Gwen from swimming makes the incident both an attempted poisoning and a key disclosure in the investigation.

The Gift and the Collapse

From their vantage point, the boys see Gwen unwrap a package and lift the lid of a box. She smiles, takes a chocolate, eats it, and quickly reaches for another. The scene initially carries the unremarkable rhythm of someone enjoying a gift. The box becomes more consequential when Gwen offers it to Mrs Bortz, apparently remembering her manners, and then abruptly puts a hand to her throat. She drops the box; the chocolates scatter across the courtyard.

Gwen lurches from her chair, bends over, and falls to the courtyard floor. The sudden change from eating sweets to a medical crisis is witnessed by the boys, who rush out of the apartment. Mrs Bortz calls out in alarm, and John Murphy bolts from his own apartment to bend over Gwen. Sonny Elmquist is also present, with his apartment door open. These immediate reactions establish how quickly the incident draws the residents together, before anyone knows what has happened.

The Suspicious Candy

Jupiter examines a piece of the fallen chocolate. Mrs Bortz seizes his arm and shakes him, crushing the candy in his hand; he nevertheless brings the mess to his nose and detects an unusual odor. He warns that there may be something in the candy that should not be there and calls for an ambulance, saying he thinks Gwen has been poisoned. His conclusion is initially cautious: he points out that the peculiar odor is suspicious, but that the boys cannot yet be sure anyone deliberately poisoned her.

That distinction matters in the first response to the emergency. The physical evidence raises an urgent possibility, not yet a confirmed account of who acted or why. The scattered chocolates are no longer simply a gift Gwen was enjoying; a piece of them has become the clue that changes the meaning of the scene. The boys’ prompt attention to it moves the incident from apparent illness toward the criminal mystery.

Hospital and Suspicion

Two hours later, Murphy and Mrs Bortz return from Central Hospital looking grim. Gwen has had her stomach pumped and is being kept under observation in a private room. The hospital laboratory is still analyzing the chocolates to determine the poison, so the precise substance remains unknown at this point. Murphy reports that the police were called and questioned Mrs Bortz about the package. He says that nobody accused her of sending poisoned chocolates, although she reacted as though she had been accused.

Mrs Bortz’s response is part of the episode’s immediate aftermath, but it does not establish her guilt. She insists she would never poison anyone, then goes to her apartment, slams the door, and locks it. Her anger gives the residents another reason to focus on her, while Murphy’s account explicitly leaves the delivery unexplained: the chocolates came through the mail, which he describes as nothing unusual. The contrast between a routine method of delivery and the concealed poison keeps the central question open at this stage.

The Later Revelation

The answer arrives later, when Jupiter explains Murphy’s motive and identifies him as the sender. Murphy had taken money from Harley Johnson’s account, where it had been held under Murphy’s guardianship, and lost it through stock-market speculation. With Harley due to come of age the following month, Murphy faced having to account for the missing money and feared that disclosure would put him in jail. He needed ten thousand dollars to replace it. The poisoning was one part of his effort to secure that money: he sent the chocolates to make Gwen too ill to swim.

This later account changes the apparent shape of the courtyard incident. At first, the box’s arrival through the mail and Mrs Bortz’s presence beside Gwen make the sender uncertain; the hospital visit confirms poisoning but does not identify its author. Murphy’s confession connects the attack to the larger scheme and makes clear that Gwen was targeted to interfere with her swimming. Jupiter also states that the poisoning was among Murphy’s crimes, alongside a burglary and an attempt to extort money from Fenton Prentice. Harley has forgiven Murphy, but the matter is now for the courts. The event therefore ends not with the poison identified in the available account, but with responsibility and motive exposed: an ordinary box of chocolates has become evidence of Murphy’s desperate attempt to conceal his financial wrongdoing.