In the serene town of Ilium, New York, Billy Pilgrim (Michael Sacks) begins to articulate his reflections in a letter to the editor. Unbeknownst to him, this moment of contemplation will catapult him back into the tumultuous events of World War II. As he finds himself on the front lines in Belgium, Billy faces the grim realities of warfare alongside his fellow American soldiers, who soon fall into the hands of the German army. Suspense looms heavily over him, particularly due to the vengeful intentions of Paul Lazzaro (Ron Leibman), a former comrade in captivity who harbors a deep grudge against him. Within the confines of their POW camp, Billy forms a profound connection with the wise and experienced Edgar Derby (Kevin Conway), who stands up for him during crucial moments.

As the conflict intensifies, Billy becomes part of a harrowing journey to Dresden, Germany, where their group must choose a leader. To everyone’s shock, he advocates for Edgar Derby over Lazzaro, who has put his own name forth. The others rally around Derby, and he is selected as their commander. However, this fleeting victory is shattered as they are sent to Slaughterhouse-Five, a facility that will soon witness devastating atrocities.

The deafening wail of sirens announces the beginning of the Allied forces’ relentless firebombing of Dresden. Billy watches in horror as the city disintegrates into chaos, resulting in the loss of approximately 100,000 lives. As the ashes settle, the POWs search through the wreckage for survivors, where Billy’s enduring friendship with Derby faces its ultimate test, leading to a heartbreaking conclusion as Derby meets his end at the hands of Nazi soldiers.

In the wake of such horror, Billy seeks healing in the embrace of love, marrying Valencia (Valerie Perrine), whose father runs an optometry school. Their marriage brings forth two children, Robert and Barbara. However, as Robert matures, his inner turmoil leads him to reckless actions, including vandalism that jeopardizes his future. Billy is able to intervene and secure his son’s release from law enforcement.

Their family embarks on a flight to an optometry convention, but Billy is soon struck by a vision — an ominous premonition that foretells the crash of their aircraft. Tragically, his forewarning comes true; the plane spirals down, claiming the life of Valencia’s father, Lionel Merble. Although Billy survives, he finds himself recuperating in a hospital bed, grappling with the immense weight of loss.

As fate continues to unfold, Valencia sets out to see him but encounters a series of unfortunate events that lead to her tragic death from carbon monoxide poisoning in her car. Determined to move forward, Billy leaves the hospital alone, despite the protests of Barbara. Meanwhile, Robert has transformed, enlisting to fight in Vietnam. Billy’s quest for solace takes a surreal turn when he is suddenly transported to the alien world of Tralfamadore, where he meets the dazzling Montana Wildhack (Holly Near). The inhabitants of Tralfamadore reveal to him a philosophy of time that transcends earthly confines; they explain that life is a series of disconnected moments, and upon death, an individual can revisit significant experiences while forsaking the painful ones.

The Tralfamadorians express a desire for Billy and Montana to bond, hoping to continue their kind. As the two find love within this extraterrestrial realm, they welcome a child named Billy Jr. Back on Earth, Billy finds himself in a contentious conversation with Barbara, debating the reality of Tralfamadore. Possessing the extraordinary gift to navigate through past and future timelines, Billy reveals a chilling vision of his impending death, where an elderly Lazzaro takes aim at him during a speech about Tralfamadore, sealing his fate in an inescapable cycle of destiny.