"Invitation to Murder" sees Herman Lewent hiring Wolfe to investigate his uncle Theodore Huck, who controls his family's finances after the death of Huck's wife Beryl. Lewent has asked for Huck to provide more than the $1,000 a month Beryl sent, but he has refused, and Lewent believes one of three female employees - secretary Dorothy Riff, nurse Sylvia Marcy, and housekeeper Cassie O'Shea - is seducing Huck into cutting off payment. When Archie and Lewent go to the house to investigate, Archie shortly finds Lewent dead in his room from a blow to the head. His investigation uncooperative, Archie tricks Wolfe into coming to the house by faking an attack on himself, and it isn't long before the great detective is able to uncover the murderer.
In "The Zero Clue," Archie prepares to question mathematician Leo Heller, who believes one of his clients committed a crime, but finds the office empty. That afternoon, Cramer comes to the office to report that Heller's body was found in an office closet, an arrangement of pencils on his desk seeming to form a sideways NW with an extra stroke and a torn eraser forming a dot between the symbols. Wolfe, spotting the meaning of the clue, speaks with all of Heller's clients, looking for instances of the number six, but the number figures in all clients' accounts. However, a chance remark from the last one reveals the true meaning of Heller's clue, illuminating the truth to Wolfe.
Finally, "This Won't Kill You" sees Wolfe and Archie in attendance at the final game of the World Series, only for several Giants players to play uncharacteristically poorly. An investigation of the locker room reveals that those players' drinks were drugged, and star rookie second baseman Nick Ferrone is missing. After Archie finds Ferrone's body, he follows Lila Moyse, wife of backup catcher Bill Moyse, while Wolfe concentrates on one small fact that points in the direction of one person. While Archie's trail puts him in danger, both he and Wolfe are led to the truth behind the crimes.
Tropes in this work: (Tropes relating to the series as a whole, or to the characters in general can be found on Nero Wolfe and its subpages.)
- Absence of Evidence: The one little fact that tips Wolfe off to Nick Ferrone's murderer is that Beaky Durkin showed no reaction to Ferrone's absence from the lineup in the biggest game of his career, never even leaving his seat, giving rise to the supposition that Beaky already knew Ferrone was dead.
- Batter Up!: Nick Ferrone is offed with a blow from a baseball bat.
- Big Secret: Several of Leo Heller's innocent clients are embarrassed to say why they wanted to see him. One wanted Leo to make a mathematical estimate of how long his wealthy aunt would live so he could borrow against his inheritance. Another needed help doing her job and was afraid of showing weakness to ambitious subordinates. The third was receiving blackmail notes.
- Contrived Coincidence: In ''The Zero Clue," a Dying Clue makes Wolfe look for the number 6 while interviewing the suspects. It plays a role in every single one of their stories, even though the dying clue really meant 302 and not 3x2. Wolfe even lampshades the coincidence.
- Dying Clue: Leo Heller left one in the arrangement of pencils on his desk. Cramer is convinced it's a sideways NW, representing Nero Wolfe. It's actually the number 302 in ancient numerical writing.
- Hidden in Plain Sight: Huck moves Lewent's body by hiding it under the thick blanket on his wheelchair.
- One Steve Limit: The Giants' scout is named Beaky Durkin, presented as unrelated to Fred Durkin.
- The Unsolved Mystery: It's never revealed who was blackmailing Mrs. Tillotson.
- Unwitting Instigator of Doom: Archie's spontaneous visit to Leo Heller's office causes the murderer to realize that Heller suspected them of a crime and had consulted Wolfe, leading to Heller's death.
- Villainous Breakdown: The killer in "The Zero Clue" has a Technically a Smile expression while trying to counter Wolfe's accusation and then tries to flee from the room.