Lost premiered back in 2004, basically kick-starting the Golden Age of Television. Over the course of six seasons and 121 episodes, it raised more questions than it was eventually able to answer, which led to a divisive series finale. While some fans loved it for staying true to the show’s central themes, others loathed it for failing to provide a satisfying conclusion to all those compelling mysteries.
Regardless of where you stand, you have to admit that the series was extremely influential, which makes picking the most important episodes of Lost a particularly difficult endeavor. What started off as an engaging drama about the survivors of a plane going down quickly evolved into a mind-bending sci-fi show that tackled larger-than-life themes, like faith versus science and good versus evil. To this day, Lost remains a layered and complex show - so much so that missing only a couple of episodes can leave any viewer scratching their head in confusion. The beauty of Lost lies in the character development, so if you’re planning a rewatch, we strongly advise you commit to all 121 episodes.
However, if you’re just looking for the greatest hits, we're not about to tell you what you can't do. The installments listed below are all essential to the show’s overall narrative, whether they feature long-awaited reveals or character introductions/demises that went on to shape the story moving forward. Vote up the ones you believe had the most impact during the show’s run.
Flashbacks were always a big part of Lost, but this is the episode that revealed just how important they were for character development. In Walkabout, viewers find out that John Locke, who will grow to be a major player in the Lost universe, used to be confined to a wheelchair prior to landing on the island. While everyone around is freaking out after the accident, Locke is living through an actual miracle: being able to walk again. This also leads to a big character transformation.
The Locke in the flashbacks is not the same Locke we see hunting wild boar on the island. It’s an emotional hour of television, but it’s also an important episode as it poses one of the questions the show will tackle over its entire course: how do we really define our lives? For Locke, the island is his salvation, which leads him on a path to unravel its secrets and figure out why he's been given a second chance.
Regarded as one of the best TV pilots of all time, the first episode of Lost, a two-parter, does a tremendous job of introducing its large ensemble cast. It also hints at the supernatural nature of the island by giving the viewers a small glimpse of the Smoke Monster, having the survivors encounter a polar bear, and featuring the discovery of a mysterious radio message in French. Charlie’s "Guys, where are we?" line at the end of the episode was a surefire way to make viewers tune in to see what will happen next.
The eventful Season 2 finale sees the survivors coming head to head with The Others. Michael leads a group of them into a trap and Jack, Kate, and Sawyer end up as prisoners. Michael, meanwhile, gets Walt back and they sail off the island together. Elsewhere, Desmond and Locke discover that when Desmond previously failed to push the button, the magnetic force pulled Oceanic Flight 815 toward the island, causing the accident.
They let the timer run out again and their fates remain a mystery by the time the end credits roll. The episode’s epilogue shows a research station somewhere in a polar climate, which detects the electromagnetic anomaly, leading one of the researchers to call Penny Widmore, telling her, "I think we've found it."
In this Season 2 episode, the survivors find out that Desmond’s mission is to press a button every 108 minutes in order to prevent what he calls the end of the world. They learn more about the DHARMA initiative via a videotape in which it’s revealed that the hatch is an electromagnetic research station called The Swan. However, the computer is damaged, which leads to Desmond fleeing into the jungle. Sayid manages to repair the computer and a confrontation ensues between Locke and Jack about who should be the one to press the button moving forward. In the end, they do it and the clock resets. The episode also introduces some of the survivors from the tail end of the plane.