Sunset Towers, a luxury apartment complex on Lake Michigan, is introduced along with the Wexler family, who are the first to move in. The mysterious Westing mansion looms on the hill above.

The remaining tenants move into Sunset Towers: Judge Ford, Flora Baumbach, Sydelle Pulaski, the Hoos, the Theodorakis family, and others. Each arrival is a quick, dense sketch.

Turtle Wexler dares herself to enter the dark Westing mansion on Halloween and discovers Sam Westing's body. She is terrified but says nothing specific about what she saw.

The sixteen heirs gather to hear Sam Westing's will read aloud. They learn that one of them is his murderer and that they must play the Westing Game to discover who — and to inherit $200 million.

The heirs examine their clues and begin forming theories. Each pair reacts differently to being yoked together with a near-stranger. Turtle immediately begins trading clues and strategizing.

Heirs compare notes, trade clues, and develop competing theories. A small explosion in the building begins to suggest sabotage — or a red herring.

The heirs begin building cases against each other. Everyone looks suspicious because everyone is hiding something. Berthe Erica Crow and Otis Amber draw the most attention.

Judge Ford begins investigating Sam Westing's history and discovers that his success was built on the destroyed dreams of others. Her own past with Westing is slowly revealed.

Several heirs independently research Sam Westing. Turtle becomes increasingly convinced she can solve the puzzle if she just has all the clue pieces. The bomber strikes again.

The sabotage in Sunset Towers escalates. Suspicion falls heavily on several heirs. The heirs' true secrets begin to surface under the pressure of mutual accusation.

New clues circulate among the heirs. Turtle makes a critical connection between her clue fragments and a patriotic song. Flora Baumbach shares a secret that deepens their bond.

Grace Wexler's social performance begins to crack. Her partner James Hoo quietly dismantles her pretensions while pursuing his own agenda. Angela's internal rebellion deepens.

Judge Ford discovers her full history with Westing and must decide whether to reveal it. Sandy McSouthers' helpfulness begins to feel increasingly suspicious.

A winter storm isolates Sunset Towers. The heirs, trapped together, have their most direct confrontations. The class and racial dynamics in the building become impossible to ignore.

Angela Wexler is revealed as the bomber. She has been setting small explosive devices to sabotage her own engagement party and to assert an identity no one will let her have.

Judge Ford and Turtle independently close in on the game's real secret. Sandy McSouthers is not who he appears to be — the clues to his identity have been in plain sight the whole time.

Turtle confronts the truth about the game and about Sam Westing. She alone solves the complete puzzle. Westing, still alive, offers Turtle a private game and she accepts.

The heirs' new lives begin. The game's real effect becomes visible: not the money, but the changed people. An epilogue fast-forwards through years to show who each heir becomes.