In 1991, a gang of thieves steal a rare $10-million gem, but, in the process, two of the gang double-cross their leader, Patrick Koster (Sean Bean) and take off with the precious stone.
Ten years later, on the day before Thanksgiving, prominent private practice Manhattan child psychiatrist, Dr. Nathan R. Conrad (Michael Douglas), is invited by his friend and former colleague, Dr. Louis Sachs (Oliver Platt), to examine a "disturbed" young lady named Elisabeth Burrows (Brittany Murphy) at the state sanatorium.
Having been released from prison on November 4, Patrick and the remaining gang members break into an apartment which overlooks Nathan's apartment, where he lives with his wife Aggie (Famke Janssen) and daughter Jessie (Skye McCole Bartusiak). He is informed by Patrick that Elisabeth is only pretending to be insane to hide out in the institution from this gang that is searching for the gem. That evening, Patrick kidnaps Jessie as a means of forcing Nathan to acquire a six-digit number from Elisabeth's memory. As Nathan visits Elisabeth, she is reluctant at first, but he gains her trust later—especially when he reveals that Jessie has been kidnapped and will be killed if he does not get the number they want. Sachs admits to Nathan that the gang who kidnapped Jessie also kidnapped his girlfriend to force him to acquire the number from Elisabeth. Sachs is then visited by Detective Sandra Cassidy (Jennifer Esposito) who reveals to him that his girlfriend has been found dead. Meanwhile, Aggie hears Jessie's voice and realizes the kidnappers reside in the apartment nearby. The kidnappers send one of them to kill Aggie while the others escape with Jessie, but Aggie sets an ambush and kills him.
After Nathan takes Elisabeth out of the sanatorium, she remembers certain events regarding the gang. It is revealed that Elisabeth's father was a member of the gang that committed the robbery ten years prior and that he double-crossed them and took the stolen gem. However, other members of the gang later found him and ordered him to reveal where he had hidden the gem, subsequently pushing him in front of a subway train. The gang members were arrested immediately, and Elisabeth escaped with her doll in which the gem was hidden. She also remembers that the required number, 815508, is the number of her father's grave at Hart Island and that her doll is placed beside him in the coffin. She explains that she had stowed away on a boat that was taking her father's coffin for burial in Potter's field on Hart Island, where the gravediggers put the doll, named Mischka, inside.
Nathan and Elisabeth steal a boat to reach Hart Island. The gang members track them down and demand that Nathan give them the number they want. Elisabeth reveals the number and Patrick orders his companion to exhume her father's coffin after releasing Jessie. He finds the doll and the gem hidden inside it. He then decides to kill Nathan and Elisabeth, but Cassidy arrives before he can shoot them. Patrick's companion is shot by Cassidy, but Patrick manages to wound her. Taking advantage of the confusion, Nathan takes the gem from Patrick and throws it to a nearby excavation machine. Nathan kicks Patrick into the grave, and then triggers the mechanism which covers Patrick with earth, burying him alive. Nathan reunites with Aggie and Jessie, and invites Elisabeth to live with them.
Michael Douglas as Dr. Nathan R. Conrad
Brittany Murphy as Elisabeth Burrows
Sean Bean as Patrick Koster
Guy Torry as Dolen
Jennifer Esposito as Det. Sandra Cassidy
Famke Janssen as Agatha "Aggie" Conrad
Oliver Platt as Dr. Louis Sachs
Skye McCole Bartusiak as Jessie Conrad
Shawn Doyle as Russel Maddox
Victor Argo as Sydney Simon
Conrad Goode as Max Dunlevy
Paul Schulze as Jake
Lance Reddick as Arnie
Aidan Devine as Leon Edward Croft
Alex Campbell as Jonathan
Arlene Duncan as Aide
Judy Sinclair as Zelda Sinclair
Larry Block as Doorman
David Warshofsky as Ryan
Darren Frost as Janitor
Philip Williams as Large Cop
Louis Vanaria as Cop at Scene
Daniel Kash as Detective Garcia
Lucie Laurier as Vanessa
Isabella Fink as 8 Year Old Elisabeth
Ray Iannicelli as Man at Marina
Colm Magner as Cop #1
Cyrus Farmer as Officer #1
Martin Roach as Transit Cop
Patricia Mauceri as Sofia
based on the novel Don't Say a Word by Andrew Klavan