Perry Mason and Pete Strickland are hired by an attorney to solve a perplexing case: the brutal kidnapping of a one-year-old whose parents were targeted for a $100,000 ransom.

Following one of her trademark barn-burning sermons, Evangelical preacher Sister Alice (Tatiana Maslany) offers the Dodsons the church's full moral and financial support - much to her mother Birdy's (Lili Taylor) dismay. During a routine domestic intervention, beat cop Paul Drake (Chris Chalk) is re-routed to a gruesome crime scene, where he follows a confounding trail of evidence. Mason (Matthew Rhys) is left incensed by a jaw-dropping admission from Baggerly (Robert Patrick) and, after pressing Emily Dodson (Gayle Rankin) on her husband's alibi, finds himself confronted by an outraged Della Street (Juliet Rylance). Detectives Holcomb (Eric Lange) and Ennis (Andrew Howard) use Drake's (Chris Chalk) findings to their own advantage.

In order to gain an advantage over E.B. and team, wily district attorney Maynard Barnes (Stephen Root) goes public with a shocking new development. Mason (Matthew Rhys) and Strickland (Shea Whigham) get unauthorized access to physical evidence with help from Virgil (Jefferson Mays), Mason's connect at the city morgue. Later, Mason attempts to extract information from a withholding Drake (Chris Chalk), who's weary of Holcomb (Eric Lange) and Ennis' (Andrew Howard) watchful eyes. Della (Juliet Rylance) notices a change in E.B. (John Lithgow), who seems uncharacteristically out of sorts.

Mason (Matthew Rhys) and Strickland (Shea Whigham) lean on Virgil (Jefferson Mays), again, for extra-legal assistance. Following Sister Alice's (Tatiana Maslany) recovery from a frightening episode, Birdy (Lili Taylor) urges her daughter to renounce her claims about baby Charlie. E.B. (John Lithgow) faces the reality of his financial situation and takes his frustrations out on Della (Juliet Rylance).

While Mason and Della are up north, Strickland tracks down the sergeant assigned to the Dodson case. Mason drops in on his ex-wife Linda and son Teddy. Della sets out to find Mrs. Dodson more capable legal representation.

Perry is having difficulties functioning in court, especially when new details are revealed.

Della presents a stubborn Mason with her case for putting Emily on the stand; Mason, Strickland, Della, and Drake attempt to tie up loose ends as the trial comes to a close.

1933. In the months following the Dodson trial, an aimless Perry leans on Della to keep the law firm afloat. While Paul accepts a job from an unlikely source, corrupt oil scion Brooks McCutcheon recruits Detective Holcomb in his quest to reshape the future of Los Angeles.

While the DA focuses on two brothers from Hooverville as their prime suspects, a discovery pushes Perry closer to the case. Later, Della goes on a date with a new flame while Paul wrestles with a shocking truth.

Rafael and Mateo are discriminated in both jail and court. Perry continues to pursue justice and confronts Lydell McCutcheon. Della gets help from Camilla.

Paul's shocking discovery brings the brothers' testimony into question. Perry pursues a plea deal. Della continues her search for answers.

Facing life in prison, Rafael recounts a deadly incident caused by the McCutcheons. Paul searches for a possible accomplice landing him in danger, and Perry makes a convincing demonstration in court.

With Holcomb subpoenaed, he helps Perry with some vital information to push the verdict in the Gallardos' favor, only for Mason to be blindsided. Della continues to foster her relationships with Camilla and Anita.

Facing career-ending accusations and potential jailtime, Perry must turn to Strickland for help. With the Gallardos' fate in the balance, Della presses Hamilton for answers, while Paul and Clara chase a dangerous lead.

As their final day in court nears, Mateo and Rafael prepare for the worst, while Perry, Della, and Paul work with an unlikely ally to sway the prosecution's hand. Perry faces the consequences of his relentless pursuit of justice.