Killian Maddox, a troubled grocery store employee, grapples with his mental health while being deeply invested in bodybuilding. Living with his grandfather, affectionately known as "Paw-Paw," the shadow of his family's past looms large, particularly the haunting memory of his father's tragic murder-suicide that targeted his mother. Driven by an overwhelming desire to excel in bodybuilding, Killian's journey is tainted by the negative consequences of his steroid use, which leads to a host of physical ailments. His emotional volatility, marked by unpredictable outbursts, often prevents him from genuinely connecting with his feelings.
As he prepares for an upcoming bodybuilding competition, he courageously attempts to express his feelings for his co-worker Jessie, played by Haley Bennett, during what should be a casual shopping trip. However, his awkwardness proves to be a barrier, leading to an uncomfortable situation. Parallel to this, he idolizes fitness champion Brad, whose silence in response to Killian's heartfelt letters only adds to his frustrations. In these letters, Killian shares his admiration for Brad and even includes his phone number, desperately hoping for a reply.
Things take a darker turn when Killian confronts a local painter about the state of his grandfather's house, feeling angered by the refusal to repaint it as "Paw-Paw" insists it is too thin. His frustration culminates in a destructive outburst, resulting in damage to the painter's shop. Following this, Killian takes Jessie out to a dinner that quickly spirals into a revealing moment of trauma, where he unloads the heavy burden of his parents' deaths alongside his aspirations in bodybuilding. The evening ends with Jessie leaving him feeling lost and alone.
As tensions mount, Killian is brutally assaulted by the painter's nephew and friends just before his next competition. Ignoring his injuries, he drives to the event, but things go awry when he collapses on stage, waking up in a bathtub, icing his body to soothe his pain.
Despite the chaos, Killian masks his violent thoughts and tumultuous life from his counselor, at one point trying to connect with a woman known as Pink Coat but unable to follow through after she sets boundaries. The darker aspects of his life continue to intensify: he is fired from his job and encounters the painter’s nephew again, inciting a harmful scene in a diner. His stress drives him to arm himself, purchasing guns as a coping mechanism for his spiraling mental state.
The narrative takes an unexpected turn when Brad reaches out, prompting Killian to a photo shoot that leads to a brief sexual encounter. However, the initial connection fades as Brad returns to silent treatment, leading Killian to fantasize about violence. He breaks into a judge's home, demanding the man to strip and pose at gunpoint as revenge for a past criticism, reflecting his deep-seated anger.
During a gripping montage of his life, Killian attends a posing show hosted by Brad, conceiving a violent fantasy of shooting him on stage. Yet, a pivotal moment of clarity prevails as he opts to leave without acting on these impulses. Upon returning home, he finds solace in Paw-Paw's comforting embrace, leading him through a cathartic breakdown. In a symbolic act of liberation, he disposes of his gun and steroids, finally resolving to recommit to his bodybuilding dreams, all while capturing the essence of his struggles through a reflective voiceover.
