Moderately successful criminal defense attorney Mickey Haller, represented by Matthew McConaughey, navigates the bustling streets of Los Angeles County from his unique office—a Lincoln Town Car—driven by a former client serving his legal fees. Haller has largely dedicated his career to defending common criminals, but everything changes when he becomes involved in a case that could define his profession: Louis Roulet, a charismatic Beverly Hills playboy and the son of real estate mogul Mary Windsor, accused of savagely beating a prostitute.
At first glance, the case seems uncomplicated. Roulet’s narrative portrays him as falsely accused, merely a victim of circumstance, while Haller and his investigator, Frank Levin (William H. Macy), meticulously dissect the evidence, uncovering striking similarities between this case and a previous one that caused a wrongful conviction for Jesús Martínez (Michael Peña). This spirals Haller into doubt, questioning whether he did enough to defend Martínez, who has steadfastly maintained his innocence from prison.
As Haller delves deeper, he spends time with his ex-wife, Maggie McPherson (Marisa Tomei), a prosecutor whose disdain for Haller's defense tactics only complicates matters further. She's critical of his commitment to clients who may actually merit punishment, and Haller begins to see the cracks in his righteous facade as he navigates legal and ethical dilemmas. Doubt festers when Martínez reacts violently to Roulet’s photograph, igniting suspicions in Haller that Roulet may actually be responsible for the past murder that unjustly imprisoned Martínez.
The stakes escalate when Levin is found dead under suspicious circumstances right after hinting he’d uncovered evidence that could turn the Martínez case on its head. With Haller unfortunate to be implicated in Levin's murder due to a weapon linked to him, he finds himself in a race against time to exonerate his ally and maintain his own innocence.
Amidst these unfolding events, Haller conducts a brutal cross-examination of the battered prostitute, striving to steer public perception in favor of Roulet. Success temporarily seems at hand when the defense successfully has all charges dismissed. While Roulet basks in his newfound freedom, it isn't long before law enforcement closes in on him for the separate murder, galvanized by information Haller extracted from a witness.
In a desperate attempt to protect his family from Roulet’s wrath, Haller arms himself, anticipating the playboy's next move. As events crescendo, Haller confronts Roulet, who derisively warns him about his inability to safeguard his loved ones perpetually. The tide turns dramatically when a group of bikers, previously represented by Haller, viciously attack Roulet.
In a final twist of fate upon his return home, Haller is confronted by Roulet's mother, who fatally wounds him with Haller’s own weapon before confessing to the murder of Levin. Despite his injuries, Haller regains composure and retaliates, eliminating the immediate threat.
After his hospital stay, Haller uncovers further evidence linking Roulet to the murder case—critical insights that may prove pivotal for Martínez's release. With a renewed sense of purpose and justice as his priority, Haller prepares to embark on his next challenging case, determined to uphold the integrity of his profession.
