Crow has been arrested. In the wake of the extraordinary events that have occurred, the remaining players sit in stunned disbelief. Turtle laments Sandy’s death, and Denton Deere, who had noticed a mean bruise on the stricken man’s shin, remarks that she should not have kicked him. Turtle denies having done so, insisting that the only person she has kicked recently was Barney Northrup. Doug Hoo observes that Sandy McSouthers was the mysterious individual playing chess with Theo, who in turn notes that the former doorman’s last move had been a foolish one and resulted in the loss of his queen.

As Judge Ford remembers that the “queen’s sacrifice” was a deception Sam Westing liked to use to defeat her when she had played against him as a child, Turtle thinks about the crooked false teeth at Sandy’s dentist and his surreptitious wink before he died. When Judge Ford reveals the relationship between Westing and Crow and the tragic story of their daughter, Violet, Otis Amber comments that it is Crow’s birthday. Turtle recalls that Sandy had said that today was his wife's birthday and is seized by a sudden realization; she asks to see Angela’s copy of the will. Along with J. J. Ford, Turtle is beginning to understand that Sam Westing has sacrificed his queen, Crow, as a diversion—the game has not yet been won!

In a final, gutsy move to determine the truth, Turtle stages a mock trial. Her first witness is Chris Theodorakis, who asserts that the person with the distinctive limp whom he had seen entering the Westing mansion on Halloween had been Doctor Sikes, Sam Westing’s friend.

Otis Amber is called up next and reveals to everyone’s surprise that he is a licensed private investigator. Otis had been assigned by Sam Westing many years ago to find his former wife, Crow, and to watch over her. By the time his services were no longer needed, Otis had developed a deep friendship with the woman and decided to stick with her. More recently, Barney Northrup had contracted Otis to investigate J. J. Ford, George Theodorakis, James Hoo, Gracie Windkloppel, Flora Baumbach, and Sybil Pulaski; instead of Sybil, Otis had targeted Sydelle Pulaski by mistake. Ironically, J. J. Ford had then hired Otis to get information on all the heirs. Otis had investigated everyone for her except the judge herself and her partner, Sandy, making the doorman the only individual never examined for any of his employers. Sandy who had enlisted Otis’s aid in telling the scary story to the kids on Halloween, Doctor Sikes had drawn attention to the supposedly deserted Westing house by building a fire in the fireplace. Turtle had subsequently gone inside, where she was lured by Sikes’s whispers and found the body of Sam Westing.

Denton Deere is called to the stand after Otis Amber. In answer to Turtle’s pointed questions, he admits that the body in the coffin on the first day of the Westing game could have been a wax dummy and affirms that Sandy had a bruise on his shin when he collapsed. Sydelle Pulaski then testifies about a missing word in her transcript of the will, proving that it had never been specified exactly what the players were to look for. Following Sydelle, J. J. Ford is asked to produce the letter of sanity she had been given at the original reading of the will; she finds that the envelope that once held the document now contains a receipt indicating that, by signing the two game checks she received over to Sandy, her debt to Sam Westing for her education has been repaid in full.

Turtle senses that victory is tantalizingly close, but she still cannot pinpoint the exact answer to the Westing game. Going over the evidence, she proposes that Westing had still been alive when the will was read but is now dead. Westing had said that his “life was taken...by one of [them]”—indeed it had been, by Sandy, when Sam took on his identity. But now Sandy is gone, too.

Turtle does not mention Barney Northrup, whom she knows is also Sam Westing because of the bruise; she has not figured out how he fits into the scheme. In addition, she suspects that Sandy is not really dead, but for the purposes of the game, she lets the players believe that he is. Turtle muses that Windy Windkloppel had taken three names—Samuel Westing, Barney Northrup, and Sandy McSouthers—and is reminded of the words of the will that assert, “The heir who wins the windfall will be the one who finds the fourth.”

Suddenly, Turtle understands that Windy Windkloppel has taken four names, not three, and she now knows what the fourth name is. When the heirs, having been led to believe that the answer to the game is Sandy, close the trial with “one minute of silent prayer for...good old Uncle Sam,” only J. J. Ford discerns that Turtle has a secret.