The show introduced a massive ensemble cast: Dr. Jack Shephard (Matthew Fox), the reluctant leader with crippling daddy issues; Kate Austen (Evangeline Lilly), the fugitive with a conscience; John Locke (Terry O’Quinn), the paralyzed man who could suddenly walk, whose faith in the island’s magic bordered on religious zeal; and Hugo “Hurley” Reyes (Jorge Garcia), the lovable millionaire cursed by bad luck. They were joined by a con man, a torturer, a pregnant Australian, a Korean couple who couldn’t communicate, and a rock god junkie.

In the pantheon of television, few shows have inspired the kind of fervent, obsessive, and ultimately fractured devotion as ABC’s Lost . Premiering in 2004, it arrived at the perfect crossroads: the tail end of appointment viewing and the dawn of the digital forum. It was a watercooler show for the age of the spoiler. For six seasons and 121 episodes, it dragged its audience through a jungle of mysteries, philosophical riddles, and emotional gut-punches, only to leave half of them cheering and the other half throwing their remote controls at the screen.

For three seasons, Lost mastered the art of the drip-feed. The opening of the hatch—the season two premiere revealing Desmond Hume (Henry Ian Cusick) living in a swan station, pushing a button every 108 minutes to prevent the apocalypse—is a top-ten television moment of all time. Forums like The Fuselage and DarkUFO exploded with theories: time travel, parallel dimensions, purgatory, a scientific experiment gone wrong. The showrunners, Damon Lindelof and Carlton Cuse, encouraged the mania. They promised that it all meant something.

But then, cracks appeared. Season three’s opening stretch dragged, focusing on the “Others”—the island’s mysterious inhabitants led by the chilling Ben Linus (Michael Emerson)—in a cage arc that felt like spinning wheels. The network famously demanded an end date. Lindelof and Cuse negotiated: three more seasons, 48 episodes, finale . This was a turning point. They knew the destination. The question was whether the journey would hold. The pivot happened in the season three finale, “Through the Looking Glass.” In one of the most famous twists in TV history, the final flashback revealed Jack screaming, “We have to go back!” It wasn’t a flashback. It was a flash-forward . They got off the island. And life was hell.

In the decade since Lost ended, prestige TV has exploded. Game of Thrones , which also infamously botched its landing, owes Lost a debt for proving that fantasy and genre could be mainstream. The Leftovers (also by Lindelof) refined the Lost formula into pure grief. Yellowjackets literally copied the plane-crash-with-mysteries blueprint. But none have replicated the feeling of watching Lost live.

From that moment, Lost abandoned the pretense of hard sci-fi. It leaned into the metaphysical. Season four introduced the “freighter folk,” time flashes, and the tragic backstory of Desmond’s constant, Penny. Season five went full Back to the Future , with the remaining cast skipping through time, blowing up hydrogen bombs, and becoming the very cause of the incident they were trying to prevent. The show stopped answering questions and started asking harder ones: If you could change the past, should you? Is destiny a comfort or a cage?