Harry Washello and Julie Peters meet by the La Brea Tar Pits, instantly drawn to each other and plotting a late-night reunion. What starts as a bright afternoon romance becomes a tentative commitment as they set a meeting for midnight. But a freak power failure disrupts everything. Harry’s alarm stays silent long enough to delay the date, and Julie, unable to reach him, leaves for home with a mix of hope and worry.
When Harry finally wakes, he realizes what has happened and rushes to Julie’s workplace, arriving at 4 AM. He tries to reach her again, this time from a payphone, and leaves a heartfelt apology on her answering machine. Before the call ends, a second ring snaps him to a terrifying possibility: a frantic man named Chip urgently warns that nuclear war will begin in under 70 minutes. Chip’s plea is cut short when he realizes he dialed the wrong area code, and an unfamiliar voice answers, telling Harry to forget everything he just heard and disconnect. The moment leaves Harry unsettled and doubting, yet he can’t shake the sense that something catastrophic is unfolding.
Back in the diner, the patrons are skeptical, but a determined woman named Landa begins to verify the alarming reports. She discovers launch codes are real and, sensing imminent danger, quickly organizes a flight out of Los Angeles. She flies to a distant Antarctic compound where life seems safer, pulling others with her as the city spirals into chaos. Harry, still shaken, joins the others’ exodus by hopping into the group’s delivery van, only to jump out when he realizes Julie isn’t with them and he won’t abandon her. The story widens from a single couple’s fear to a city-wide scramble as people scramble to survive.
With time running out, the evacuation becomes a scramble of strangers who initially operate in the dark, unaware that a nuclear strike could redefine their world. Along the way, Harry’s well-meaning actions inadvertently cause several deaths, leaving him unsettled and deeply driven to get to Julie’s side. When the couple reunites, Julie questions whether there has been any official confirmation of an attack, leaving them to decide whether to trust the ominous warnings or cling to the possibility that it could all be a false alarm.
Desperate to reach safety, Harry tracks down a helicopter pilot and arranges to meet on the roof of the Mutual Benefit Life Building, where Landa coordinates a rescue with a helicopter and a supply run. Julie, meanwhile, searches for her own pilot, and as the city teeters on the edge, Los Angeles descends into unbridled chaos. A chilling realization settles in: even if they escape, there might be no turning back.
When they finally reach the rooftop, the scene is eerily empty except for a drunken co-worker who lingers on the edge of the chaos. A missile streaks across the sky, confirming the danger. The promised helicopter returns, its pilot badly wounded but determined to fulfill his pledge to retrieve them. They lift off just as the city’s nightmare accelerates into view, only to crash into the tar pits below when an EMP detonation sends the craft tumbling.
As the helicopter sinks into the natural asphalt, the cabin fills with tar. Harry consoles a terrified Julie, offering a hopeful if grim outlook: someday their fossils might be found, or they could be preserved in a museum, or even transformed into diamonds by fate. Julie, clinging to him, finds solace in his words as the world around them collapses. The screen fades with the implication that a direct nuclear strike has occurred, leaving their fate sealed in the murky depths of the tar and the uncertain memory of a city that once hoped for a late-night miracle.
