Ed Avery, James Mason a schoolteacher and family man, endures bouts of severe pain and sudden blackouts that slowly gnaw at his daily life. His wife Lou Avery, Barbara Rush, grows increasingly worried as the episodes intensify, and when Ed collapses at home, he is rushed to the hospital. A chance visit from a cab driver at the hospital leads Lou to learn that Ed also works part-time as a dispatcher to help pay the bills. They share a tender kiss, and as the doctors prepare to step out, Ed bluntly declares that there are no more secrets between them, marking a tenuous shift from secrecy to uneasy openness.
The diagnosis is polyarteritis nodosa, a rare and dangerous inflammation of the arteries, and it is soon clear that Ed has only months to live unless something drastic changes. He agrees to experimental cortisone therapy, clinging to the hope that the steroid treatment will restore some normalcy. To everyone's relief, Ed makes a remarkable recovery and starts to spend more time with Lou and their young son, Richie. But triumph gives way to trouble as Ed begins to abuse the cortisone regimen. Mood swings become explosive, and he lies to his doctors to obtain more of the drug. Although he has taken a sabbatical from teaching, he remains active on the local Parent–Teacher Association board, where his abrasive manner and arrogance flare during a meeting—an outburst that shocks Lou and even alarms a colleague, Wally Gibbs, who tries to intervene.
When Wally Gibbs visits the Avery home to talk with Lou, Ed returns and hurls a cutting remark, insinuating that Wally is drawn to Lou. He then targets Lou with verbal assaults of his own, insisting that she is intellectually inferior and unworthy of their marriage. Driven by a growing dependence on cortisone, Ed forges a new prescription after consuming another full course, escalating the danger to himself and his family. The tension spills over during a game of football with Richie, where Ed becomes dangerously aggressive, pushing the boy well beyond his limits and forcing Lou to confront the consequences of his deteriorating condition.
As Wally presents research suggesting that high-dose cortisone can trigger psychosis, Ed’s grip on reality loosens further. He rebuffs any concern, reminding Lou that his condition will recur without the drug and that he cannot afford to stop. A chilling moment follows at dinner when Ed announces his plan to divorce Lou, delivering a stark warning about the future if things do not change. The next day, Richie, desperate to help, raids Ed’s medicine cabinet in hopes of stealing a few pills. When Ed corners Richie in his room, Lou phones Wally Gibbs for support, and Ed’s temper boils over in a violent moment. He reads a Bible passage about the binding of Isaac to chastise Richie, then proclaims a murder–suicide plan, intending to kill Lou and Richie before taking his own life. In a frantic sequence, he locks Lou in a coat closet, blasts the television to deafening levels, and crosses to Richie's bedroom, wielding a blade from a pair of scissors.
Wally bursts into the house and manages to subdue Ed, who is left unconscious and then hospitalized again. Dr. Norton, Robert F. Simon, informs Lou that the cortisone may have caused irreversible brain damage and that Ed could be left with lasting cognitive impairment. He also notes that if Ed can recall the events of the past weeks, there might be a chance for some mental recovery, but only with carefully controlled, strictly measured doses of the drug to sustain his life. Lou and Richie visit the bedside, and when Ed finally awakens, he is disoriented at first but slowly recognizes his wife and son. In that quiet moment, he reaches out to them with a genuine, if fragile, embrace, signaling a hard-won, though fragile, moment of reconciliation amid a fraught medical ordeal.
The film traces a harrowing arc of illness, medication, and the fragility of a family under pressure, balancing clinical detail with intimate, emotional stakes. Through Ed’s volatile rise and harrowing descent, it scrutinizes the double-edged nature of medical treatment and the unpredictable toll it can take on those who trust in it most.
