Justine Last is a thirtysomething woman feeling increasingly trapped in her mundane life in a small Texas town alongside her husband, Phil, who spends most of his free time indulging in marijuana with his buddy, Bubba. While Phil yearns to start a family, Justine is hesitant. Each day, she works at Retail Rodeo, a local big-box store, alongside her co-workers Cheryl, Gwen, and the security guard, Corny.
When a new cashier, Holden, joins the team, Justine takes the opportunity to introduce herself. As they grow closer, she reveals her feelings of being undervalued at home. However, when Holden attempts to escalate their relationship into something more intimate, Justine turns him down, prompting Holden to write a letter threatening that she will never see him again unless she meets him at 5 p.m. that very day. Reluctantly, she agrees to meet him at a motel, where they ultimately sleep together.
As Justine's marriage begins to crumble under the weight of her affair with Holden, tensions rise. One fateful night, she spots Bubba's truck parked outside the motel, and fearing he might suspect something, Justine tells Holden she can no longer see him. Bubba, however, has other plans; he blackmails Justine into a sexual encounter. Unknown to her, Holden watches through the window, sparking further chaos.
The following day, Holden, devastated and drunk, confronts Justine in her car, hurling accusations and threats, even suggesting he would kill her husband to free her. In the midst of this emotional turmoil, Justine confesses her troubles to Holden’s parents, claiming he is mentally unstable and has been imagining their romance. Meanwhile, after experiencing an off day, Justine takes a pregnancy test, which yields a positive result. While Phil celebrates the news, Justine internalizes her anxiety about the baby’s true paternity.
The complications escalate when suspicions arise that Holden has stolen $15,000. Justine faces her boss, Jack, regarding their relationship while Holden nonchalantly mentions his plans to run away with her, bragging about the theft. After a tumultuous day filled with unexpected confrontations, Justine returns home to find Phil, Bubba, and Bubba’s girlfriend celebrating her pregnancy. A surprising phone call reveals Phil's infertility status, leading to mixed feelings and escalation.
In the days that follow, Justine grapples with her desires and the consequences of her actions. As she makes a fateful choice regarding her future with Holden, news breaks of a police standoff with him at a hotel, culminating in his tragic suicide. The day after, Justine is caught in the web of lies surrounding her relationships, especially when Phil questions her fidelity. Under pressure, she falsely admits to having an affair with Corny, leading to further complications at work when Corny shows up injured.
In the heart-wrenching conclusion, Justine finds herself still toiling at Retail Rodeo, but there is a glimmer of hope when Phil arrives carrying their newborn. Holding the baby close, Justine experiences a fleeting moment of happiness, leaving the audience to ponder if she and Phil can truly find contentment amidst the chaos.
