In the summer of 1981, Alexander "Ned" Weeks, an openly gay writer living in New York City, heads to Fire Island to celebrate the birthday of his close friend, Craig Donner, amidst the picturesque backdrop of a beach house. Among the attendees are their friends, Mickey Marcus and the charming Bruce Niles, who has recently begun a romantic relationship with Craig, a young man who currently appears vibrant and healthy. However, during a stroll along the beach, Craig unexpectedly feels dizzy and collapses. Later that evening, as he blows out the candles on his birthday cake, he is overtaken by a fit of violent coughing.
Upon returning to New York City, Ned stumbles upon an alarming article in The New York Times titled "Rare Cancer Diagnosed in 41 Homosexuals." Disturbed and concerned, he visits Dr. Emma Brookner, a physician who has been treating numerous patients exhibiting symptoms of rare diseases that would typically pose little threat unless one’s immune system was compromised—an alarming trend seen primarily in gay men. While in the waiting area, Ned encounters Sanford, a patient visibly deteriorated by Kaposi's sarcoma, a rare cancer. When Dr. Brookner examines Ned, she finds him symptom-free, but she urges him to help her raise awareness about this emerging health crisis within the gay community.
Tragedy strikes when Craig suffers a series of violent convulsions and is rushed to the hospital, accompanied by Ned, Mickey, and Bruce. Sadly, he is pronounced dead shortly after arriving. Dr. Brookner recognizes Bruce as he is the former partner of another patient who recently succumbed to the disease. In response to the growing urgency, Ned organizes a meeting at his home, inviting local gay men to hear Dr. Brookner present her insights on the illness. While she can’t offer definitive proof, Dr. Brookner insinuates that the disease may be sexually transmissible, recommending that the community exercise caution regarding sexual activity to prevent further spread. However, her claims stir skepticism among the attendees, as she expresses frustration over the medical community’s reluctance to publish articles regarding the diseases widely affecting the gay population. Determined, Ned proclaims his intention to establish an organization dedicated to disseminating important information and providing support for those affected.
Ned, alongside Dr. Brookner, visits a local hospital where many of her patients are critically ill from what is now being referred to as gay-related immune deficiency (GRID). The atmosphere is grim, with hospital staff hesitant to approach the ill patients due to fear of transmission. Motivated by the dire circumstances, Ned, along with Bruce, Mickey, and several comrades—Tommy Boatwright among them—form the Gay Men's Health Crisis (GMHC). The organization rallies to raise funds for research into the disease now known as AIDS, while also implementing vital services such as counseling and a telephone hotline. Despite Ned's objections about their focus on fundraising, Bruce is elected president. To further support their cause, Ned secures the assistance of his brother, Ben Weeks, a lawyer who offers free legal counsel to GMHC, even as tensions remain due to Ben’s struggles to understand Ned’s identity.
As the epidemic continues its relentless advance, Ned seeks the aid of The New York Times reporter Felix Turner, hoping that his connections in the media could help spotlight the escalating health crisis. Felix expresses his frustration over the media's reluctance to cover AIDS comprehensively. Their previous encounter at Man's Country bathhouse leads to a romantic relationship blossoming between them.
As the disease spreads, it wreaks havoc on the lives of their circle. Tommy, grappling with the loss of friends to AIDS, begins a somber ritual of removing their contact information from his Rolodex, creating a chilling collection of "cardboard tombstones." Bruce endeavors to take his dying boyfriend, Albert, to Phoenix for a final goodbye with his mother. Initial attempts to board an airplane with Albert are met with refusal, but they eventually manage to make the trip. Tragically, shortly after arriving, Albert passes away in a state of dementia; the hospital staff's refusal to recognize him results in his body being discarded without proper respect. In desperation, Bruce resorts to bribing a funeral home to cremate Albert without a death certificate, plagued by sorrow as his mother weeps over her son's loss.
Meanwhile, Dr. Brookner faces considerable challenges in securing funding for AIDS research, only to be met with resistance from government officials who deem AIDS a low priority. As conditions worsen, Ned's aggressive methods for raising awareness alienate him from GMHC, leading to his expulsion from the group. Chaos unfolds as Felix begins to exhibit symptoms—his health declines rapidly, and in their last moments together in the hospital, he lays bare his love for Ned before succumbing to the disease.
In the aftermath of Felix's passing, Tommy silently adds another card to his growing tribute in remembrance of his lost friends. A few days later, Ned visits Yale University, where he observes the vibrant celebration of Gay Week, filled with young people dancing fearlessly in an atmosphere void of discrimination. Nonetheless, the escalating reality of AIDS continues to loom large, with the faces of those affected increasing dramatically, including Bruce, as Tommy’s cardboard tombstone pile painfully grows.
