William Banks, who, after hitting rock-bottom from his own addictions after the birth of his daughter, strikes a tentative deal with God. Now along with his unconventional team, he helps people get away from their addictions by any means necessary. William tries to help Zach, a once-promising athlete, to overcome meth addiction, but he cannot help his best friend.
The mother of a teenage surfer girl, comes to William about her daughter, who she says exhibits signs of a drug habit. The only problem is, the woman's daughter's drug tests keep coming up clean.
A suburban husband comes to William, seeking help for his wife, who is caught in the throes of an OxyContin addiction. William and his team discover that the woman is not only using Oxy, she is part of an elaborate suburban drug ring. William's crew works to cut off the group's supply lines to force the woman into treatment. But when she grows desperate to feed her addiction, how far will she go?
A mathematics professor, in a race against time to publish his research, turns to cocaine. His colleague and girlfriend seeks William's help. William must nab the professor before he loses everything, his career, his personal life, even the diner owned by his immigrant parents.
A boy asks William's to help with his father, who went to prison as a result of William's efforts. The man, now out of prison, is using the same thing that landed him there in the first place, meth. William and his team go undercover in a biker gang and discover that their mark is part of a meth ring. As he deals with this father-son relationship, William must deal with the reality that his own son is slowly pulling away from him.
William and crew infiltrate a "tent city" of meth manufacturers to find an FBI agents former partner, who developed a drug habit while deep undercover, that is delusional and dangerous. Only then does William realize that the FBI agent lied to him: the man is not only her ex-partner, but the father of her unborn child, and a pawn in a larger power struggle within the FBI.
The principal of a prestigious prep school, asks for William's help with a talented basketball player who is now "speedballing" heroin and prescription drugs. William and his team encounter resistance from the boy's blue-collar father, while the young man, in the throes of addiction, steals from a nursing home patient and engages in increasingly reckless behavior.
The wife of a horse jockey seeks out William. Her husband has used the ADD medication Adderall for years in order to make weight, but as of lately has been exhibiting hostile behavior.
An unsuccessful intervention drives a heroin-addicted woman onto the streets. Her sister hires William, but the girls' mother doesn't trust him. The mother retains the original interventionist, who considers William little more than a thug. Forced to question why he does what he does, William rushes to find the addicted woman before she allows her addiction to take over.
A gifted teenage pianist, turns to meth to cope with the pressures in her life. Rebecca's father has been supporting her habit out of fear of losing her.
Lisa moved to Los Angeles years ago with dreams of becoming an actress, but thus far, all she has managed is a steady career as an extra. When her visiting brother discovers the depth of Lisa's cocaine problem, he enlists William.
William brings Swenton into the Banks home to detox, determined to save him from the fate that Mickey suffered. Meanwhile, Akani and Darnell take on a case from drug dealer Gaza Rashburg. They infiltrate his daughter's sorority house, where Akani discovers that the girl is bulimic, while Darnell harbors a personal vendetta against Rashburg.
In the season finale, Neil and Shelly have a beautiful daughter, a wonderful home, successful careers and dangerous addictions to alcohol. Neil's father comes to William, concerned for his granddaughter's safety. William and his team make a risky play posing as Child Protective Services to remove the little girl from the house and scare Neil and Shelly straight. Can they get clean together, or will the price of sobriety be their marriage?