After being bitten by a dog named Ned, Walter finds the novel overtaking his life; he begins believing that he's detective Fingerling, the hero of the book, and is convinced that he is doomed to commit the same crime as the fictional gumshoe (Fictional character Fingerling goes slowly nuts and ends up murdering his hot-blooded Italian girlfriend) and fears for the safety of his wife and his son.

Walter also develops a quasi-kabbalistic obsession with the eponymous digits. He slowly grows more delusional and obsessed. His time of birth, his address, and other random figures can be manipulated to equal number 23 - and he can't stop thinking about the ubiquitous number. A psychiatrist, played by Danny Huston, tells Walter this is an authentic phenomenon known in certain circles as “the 23 enigma.”

This worries his wife, of course, who he suspects is having an affair with their close friend, Isaac (Danny Huston).