Do you swear to tell the truth, the whole truth, and nothing but the truth? So help you God.
Defense attorney Richard Ramsay (Keanu Reeves) takes on a personal case when he swears to his widowed friend, Loretta Lassiter (Renée Zellweger), that he will keep her son, Mike (Gabriel Basso), out of prison.
Charged with murdering his father, Mike initially confesses to the crime. But, as the trial proceeds, chilling evidence about the kind of man that Boone Lassiter (Jim Belushi) really was comes to light. While Ramsay uses the evidence to get his client acquitted, his new colleague, Janelle, tries to dig deeper – and begins to realise that the whole truth is something she alone can uncover.