On the Fourth of July, a 62-year-old delivery boy rides around a town on the edge of Lake Michigan delivering letters signed by a man named Barney Northrup—a man who does not exist. The letters invite their recipients to move into Sunset Towers, a new apartment building on the lake which, despite its name, faces east. Within days, Northrup has rented all of the homes in Sunset Towers, as well as both restaurant spaces and a medical office in the lobby. In September, the tenants move in. Hidden among them are a bookie, a burglar, a bomber, a thief, and a mistake. A “NO TRESPASSING” sign and a wire fence have been erected on the north side of the building’s property—beyond them lies the mysterious Westing estate.
On Halloween, Sandy McSouthers, the doorman at Sunset Towers, and Otis Amber, the delivery boy, spot smoke coming from the Westing manor’s chimney. They rib the teens who live in the building—Theo Theodorakis, Doug Hoo, and Turtle Wexler—by telling them ghost stories about how old man Westing has been rotting away inside for years. The other tenants notice the smoke, too—Theo’s brother Chris, who is suffering from a neurological disorder and uses a wheelchair, spies the smoke through his birdwatching binoculars, and Turtle’s engaged-to-be-married older sister, Angela Wexler, spots the smoke during a fitting with her wedding dress maker, Flora Baumbach. Turtle’s father, Jake Wexler, is a podiatrist—as he visits with a patient, Berthe Erica Crow, the building’s religious cleaning woman, Crow spots the smoke and becomes alarmed. Judge J.J. Ford and Sydelle Pulaski, two other tenants of Sunset Towers, return home and notice the smoke, too.
That night, Turtle meets Doug at the Westing estate: she is determined to win $2 for every minute she spends inside the manor. Doug sets a stopwatch as Turtle runs in. Minutes later, she runs out screaming—she has seen the dead body of Sam Westing. The next morning, Turtle finds that Westing’s death has made headlines. Turtle is excited when she reads that Sam Westing, the son of immigrants turned founder of the lucrative Westing Paper Products Corporation, is worth over $200 million. A patriot and teetotaler, Westing made his corporation vast and successful while also dismantling his employees’ attempts to organize a union. Turtle also learns about the tragedies in Westing’s past: many years ago, his daughter Violet died the night before her wedding. Not long after that, Westing and his friend, the county coroner Dr. Sidney Sikes, were in a terrible car accident which was rumored to have left Westing disfigured. Meanwhile, Otis Amber sets out on another delivery. He has 16 letters from Westing’s attorney, E.J. Plum, to deliver—tomorrow, there is to be a reading of the will at the Westing estate.
At the reading of the will, the recipients of Plum’s summonses gather. Among them are Turtle, Angela, their mother Grace, and Angela’s fiancé Dr. Denton Deere; James Shin Hoo, the proprietor of a Chinese restaurant in Sunset Towers along with his son Doug; Crow, Flora, Ford, Sydelle, Theo and Chris, Sandy, and Otis. Hoo’s wife, Madame Sun Lin Hoo, and Jake have also been summoned, but they do not attend. The will declares that the 16 potential heirs to the Westing fortune will soon be divided up into pairs of eight, handed sets of clues, and invited to play “the Westing game.” Westing’s will declares that he did not die of natural causes—one of his heirs took his life from him. The heir who “wins the windfall” will be the one who solves the mystery.
In the next room, Plum reads out the game’s pairings: Madame Hoo and Jake, Turtle and Flora, Chris and Denton, Sandy and Ford, Grace and Mr. Hoo, Crow and Otis, Theo and Doug, and Sydelle and Angela. Each pair, Plum says, will receive a $10,000 check—if anyone drops out, their partner must also forfeit the money. Both players must sign the check to cash it. Plum passes out the clues—the pairs are confused by the inscrutable slips of paper they’ve been given, on which four or five seemingly unrelated words are written. Plum ends the session by reading from one last section of the will. The will reminds the players that it is not what they have but what they don’t have that counts. It also urges the players to discover who they are (and who their partners are) deep down—but, at the same time, it encourages them to “beware” of one another.
After a blizzard, the residents of Sunset Towers are snowbound. Sydelle becomes popular as the tenants vie for a glimpse at the notes she took during the reading of the will. Turtle decides that the clues she’s been given spell out stocks she should invest her and Flora’s check into. Ford, determined to learn everything she can about her fellow heirs, enlists the help of a reporter to dig up facts about each of them. Sydelle’s notebook goes missing—and so do many other tenants’ most precious items. Ford invites all of the heirs to a party, hoping to learn more about them. The next morning, the heirs meet at the coffee shop owned by Chris and Theo’s parents, George and Catherine. Theo wants the heirs to pool their clues, but many of the others, including Hoo and Ford, are reluctant to do so. Instead, the heirs agree to allow some anonymous questions. Everyone writes down the questions they have for the other heirs on a slip of paper, and Theo reads the questions out. Before he can get to the end, however, a bomb goes off in the kitchen. The heirs leave, rattled.
Ford’s investigation continues. Her reporter turns up pictures of George and Violet Westing together at a party. Ford, knowing she needs to go deeper, calls a private investigator. Meanwhile, the bomber sets another trap in the kitchen at the Hoos’ restaurant. That evening, many of the heirs head up to Shin Hoo’s for dinner. As the restaurant is bustling in the middle of dinnertime, the second bomb goes off. Grace, who has taken a position as the restaurant’s hostess, tries to calm the guests. Sydelle sprains her ankle outrunning the blast and is taken to the hospital.
Eventually, the sun comes out and melts the snow, freeing the residents of Sunset Towers. Sandy and Ford begin compiling dossiers on their fellow heirs. As Ford gets to know the scar-faced Sandy better, she learns that he is a former boxer who was fired from the Westing Paper Products plant after trying to organize a union. Several of the heirs begin piecing together bits of the will and bits of their clues, realizing that the song “America the Beautiful” is key in solving the mystery. Some of the heirs begin breaking out of their pairs, exchanging theories in clusters. At Angela’s bridal shower, as Angela opens her gifts, one of the presents explodes in her face. The beautiful Angela is taken to the hospital with burns on her hands and face. The heirs grow even more suspicious of one another.
Suspicion flies throughout Sunset Towers as the heirs work round-the-clock to discover more about one another’s pasts. Ford and Sandy deduce a connection between Grace, whose maiden name is Windkloppel, and Crow, who was once married to a man named Windkloppel. They also learn that Violet Westing killed herself the night before her wedding after her mother arranged a sham marriage to a hack politician, pulling Violet away from her true love, George Theodorakis, whose family were workers at the Westing Paper Products plant. Ford reveals to Sandy that she grew up in the Westing house: her parents were servants there, and Westing financed her education. She has never repaid her debt to him. She and Sandy decide that Westing is not dead, but is instead likely in disguise as one of the heirs. They believe that Westing wants revenge on his ex-wife, Mrs. Westing, for driving their daughter to suicide. They realize that they must protect Mrs. Westing—she, too, has to be among the heirs.
Another bomb goes off in the elevator—Turtle confesses to being the bomber, though it was really Angela. That night, at the Westing estate, the heirs receive another $10,000, but are told that in order to win the $200 million, they’ll need to produce the name of who among them is responsible for Westing’s death. The heirs offer up their answers—some don’t offer one at all. The group moves to the library, where Plum opens up another envelope and declares that all answers are wrong. Partnerships, the document says, are dissolved—all the heirs are on their own. Plum leaves the room and locks the door. Theo suggests everyone work together. Sandy drinks from a flask as the others arrange their clues: the words spell out the lyrics to “America the Beautiful,” but several letters and words are missing. The missing letters spell out “Berthe Erica Crow.” Sandy falls to the floor, apparently having been poisoned, and dies. The police arrive to investigate. Plum reads yet another document from the will: if no one offers up the answer in five minutes, the will becomes null and void, and no one gets any money. The heirs refuse to offer up Crow’s name, unwilling to believe she is guilty. Crow, at the last minute, offers up her own name. The police lead Crow away.
After this, the heirs return to Sunset Towers and gather in Ford’s living room, where Ford and Turtle hold a “trial” to determine what has truly transpired. Turtle believes that Crow is yet another red herring and that the answer to the mystery lies in the pages of Westing’s will. Over the course of the makeshift “trial,” Turtle reveals that Otis Amber is a private investigator with three clients: Westing, Northrup, and Ford. Deducing that language in the will relating to Westing’s ashes being scattered to the “four winds”—and Westing’s original family name, Windkloppel—relate to the answer, Turtle realizes that Sandy McSouthers, Barney Northrup, and Julian Eastman, the CEO and President of Westing Paper Products, are three of Westing’s aliases. She tells the others that Sandy was Westing in disguise, but she doesn’t reveal anything about the other aliases. Madame Hoo reveals herself to be the thief and returns all the items she’s stolen from the others. Ed Plum returns with Crow, who’s been found innocent. Fireworks go off at the Westing estate. The next morning, Turtle heads out on her bike to the estate of Julian Eastman—there, greeting Eastman as “Sandy,” she proudly declares that she’s won the game.
In a series of flash forwards, the narrator reveals the fates of all the heirs. Turtle never reveals what she found to the others, but she attends weekly chess lessons at “Sandy” (Westing’s) house. Crow and Otis Amber, lifelong friends, marry each other at last. Angela returns to medical school after breaking off her engagement. Ford ascends to the Supreme Court and finances Chris’s education, paying off her debt to Westing by paying it forward; Chris goes on to become a successful ornithologist. Sydelle marries her former boss at the sausage factory. Jake becomes chairman of the state gambling commission. Doug Hoo wins an Olympic gold medal and becomes a successful sports reporter. Hoo invents paper insoles that make him a rich man before he dies at a young age. Grace becomes a restaurateur. And many years later, Turtle—now going by T.R.—becomes the head of the board of the Westing Paper Products Corporation after her mentor, Julian Eastman, dies at a ripe old age on his favorite holiday, the Fourth of July.