The Lyon's Den Season 1

John ""Jack"" Turner (Rob Lowe) has managed to evade the career expectations of others by working at his small pro-bono law clinic helping those without means who need legal representation. When the senior partner, Daniel Barrington (Kevin Cooney) at Lyon, LaCrosse and Levine suddenly dies, Terrence Christianson (James Pickens, Jr.), the head of the firm, calls on Jack to take Barrington's place. While Jack wants no part of it, Grant Rashton (Kyle Chandler) wants nothing more than to be Christianson's choice for the position. With the help of Rashton's scheming assistant, Brit Hanley (Frances Fisher), he will stop at nothing to get it. Also weaving her into the hierarchy of the firm is Ariel Saxon (Elizabeth Mitchell) who is struggling to battle alcoholism. Vying for her attention is paralegal, Jeff Fineman (David Krumholtz). With the sudden death of Turner's mentor, Barrington, Jack begins not only question his future role within the firm but the intentions of everyone around him.

Jack settles in as managing partner at his prestigious former law firm and tackles a civil case in which a longtime client and father launches a civil suit against a young man who's already been acquitted of killing his teenaged daughter—while Riley defends a 16-year-old who drove a tractor full of explosives into the Capitol Mall reflecting pool. Meanwhile, Jack is questioned clandestinely by the dogged Detective Traub about his mentor's suicide and seems unaware of the secret strategy among his legal counterparts to unseat him. In addition, Ariel is chastised by Riley for overstepping her authority as second chair for his defense of the misguided teenaged tractor driver.

Jack and Ariel go to New York to represent a famous, ambitious and sexually ambiguous fashion executive who is accused of sexual harassment by a former worker – but Jack is pressured by the clothing firm's board to arrange for a settlement. Back in Washington, D.C., Grant grows jealous of Ariel teaming with Jack, while she ponders the threat of their past intimate e-mails being retrieved and exposed. Elsewhere, Riley feels responsible when he blows off a desperate former classmate whose descent into substance abuse was triggered by an experimental drug.

Jack is somewhat confused when an old friend claims to be guilty of securities fraud as charged, and his wealthy in-laws obstruct his defense. Meanwhile, Grant Rashton represents the city in a suit against a gun manufacturer, George Riley is feeling overworked at the clinic, and Detective Traub is running out of excuses to keep Jack's mentor's death from being declared a suicide, unless he can find the missing security log from the night in question.

A serial killer on death row taunts Jack by claiming to know who was with Barrington the night he died. When a judge forces Riley to take on the defense of a young man, he considers accepting a plea bargain so that he will be home in time to take his children trick-or-treating. And Rashton is troubled by a photo Ariel stole from Jack's desk.

Jack is shocked to confront a former lover who is a Department of Justice attorney assigned to prosecute his client, an FBI agent on charges of espionage – but thanks to Grant, Jack discovers the G-man's suspicious ex-girlfriend, who is the government's key witness.

Jack receives a disturbing call from Detective Nick Traub stating he knows who the killer of Barrington is, but when Jack goes to meet him he finds the officer with a bullet in his head. Meanwhile Grant is having trouble with a client. George searches for a new job when it's decided to CLOSE the clinic. George also confronts Jack about his involvement in Zerotech. Eventually Jack is edited for his dealings with Zerotech, which he claims are totally untrue. After Jacks fall from grace Grant is appointed Managing Partner.

Jack discovers the truth about Zero Tech and Dan Barrington; Grant defends a woman who was fired from her university job after a tabloid printed a photograph of her and her fugitive brother.