Doug Varney (Rockwell) is the primary pharmacist of Woodbury, a small town, having inherited the pharmacy from his father-in-law, Walter Bishop. He is unhappily married to Kara (Monaghan), who is obsessed with cycling, winning the annual "Woodbury Classic" bike race 5 years out of 6, and running a local spinning facility, and troubled by his lack of ability to connect to his troubled son, Ethan. One day, when delivering a prescription to trophy wife, Elizabeth (Wilde), he discovers a new obsession. Elizabeth and he have a torrid affair, fueled by his own custom pharmaceutical creations, and Doug seems to start taking control of his life, beating his wife in the Woodbury Classic and bonding with his son by committing vandalism while dressed as ninja. However, things take a downward turn.
DEA Agent Andrew Carp shows up and requires access to Doug's records as a routine matter (as a result of Bishop neglecting to properly transfer ownership). Thinking he's about to be found out, Doug and Elizabeth hatch a plan to murder her wealthy and neglectful husband, Jack (Liotta) so that they can run off together with the money. Meanwhile, Doug is spiraling into addiction, unable to keep his personal and professional life in order, culminating in a frantic cross-town trek, Doug in handcuffs, a death, the return of Agent Carp, and finally, resolution.
This film exhibits the following tropes:
- Chekhov's Gunman: Noah, the delivery boy, is established early on as being irresponsible and prone to errors. In one scene, Doug even confronts him to figure out if he's drunk or high, and is told by Noah that he's just suffering from a bad hangover from drinking too much. Near the end of the film, Noah shows up dead of an overdose, with a paper trail showing that he'd been stealing and dealing pills, conveniently covering up Doug's own theft.
- Descent into Addiction: The film acts as a depiction of this trope, although it's ambiguous as to whether it was drugs, love, success, or freedom that Doug became addicted to.
- Functional Addict: Despite taking a cornucopia of drugs, Doug manages to keep his life in order for some time. However, the film does show the side effects, from hangovers to being unable to concentrate enough to drive his car later in the film. Additionally, he gets more disheveled and grey as the film progresses. At the end of the film, it's ambiguous as to whether Doug is still partaking of his own supply.
- Drugs Are Good is averted in that, even with an expert understanding of side effects and how to mix drugs, Doug is shown exhibiting negative effects from his partaking.
- Drugs Are Bad is also averted in that it's made clear from the start that some drugs are necessary to allow people to live their lives due to external and internal problems.
- Henpecked Husband: Kara refuses to let Doug take measures to help Ethan, actively sabotages his attempts when he tries, then blames him when the situation goes wrong. She belittles him for not being able to keep up with her on bike rides, refuses sex with him for flimsy excuses, and turns her microphone back on at the Spinning class so that she can tell him he's not a real man in front of those in the class.
- Karma Houdini: After stealing medications, taking them illegally, having an affair with a married woman, vandalizing his own storefront, and engineering a murder, Doug manages to get away with it all, forging a stronger relationship with his son, securing success (and his name on the sign) with the pharmacy, and a clean record with the DEA.