During its time on screen, Lost was frequently accused of making up storylines as it went along, but plenty of elements were planned out from the very start. First premiering in 2004, Lost shook the landscape of television with its compelling, character-driven mysteries, high-concept plots and cinematic production values and the show's earlier seasons became must-see viewing, as fans feverishly debated and speculated after each episode.
Due to a combination of factors, however, critical reaction and viewership began to dwindle around Lost's midway point. An ill-timed writers' strike, a lack of end goal and increasingly fantastical mysteries combined to drive a section of viewers away but, fortunately, Lost's later seasons are widely considered to have turned the show's fortunes around, despite a highly divisive finale episode. Around the time viewers began abandoning the Lost ship in significant quantities, one of the show's foremost criticisms was that the writers and producers were making things up as they went along, and that questions were being asked without an answer in mind.
Several members of Lost's creative team have admitted to only having some long-term stories sketched out from the very beginning, with other details added or changed on a more fluid basis, but it should be noted this is the norm for the vast majority of TV productions. Nevertheless, the Lost bible document, prepared by Damon Lindelof and J. J. Abrams prior to the airing of the premiere episode, confirms that some original ideas were not only planned from the start, but remained relatively untouched. Here are the long-term storylines Lost had in place from the very beginning:
The Island's Ancient History
The history of Lost's island stretches back centuries to the days of the Roman Empire and beyond, perhaps even to the very beginning of Earth's formation, and indications of this were scattered throughout the series. Whether through hieroglyphics, a destroyed Egyptian statue or the existence of a vast, ancient temple, civilizations had clearly been visiting the island over several different eras and although the specifics weren't nailed down from the very start, Lost's historical connections were always intended to emerge at some point, with the bible mentioning "evidence" of past settlements dating back centuries as part of its description of the island.
The reason for these previous visits might not have been decided upon, and a leaning towards Egyptian mythology perhaps suggests an alternative explanation was once planned, but delving deep into the past was always part of Lost's design, even if it only began to unfold in later seasons.
The DHARMA Initiative
Although the DHARMA Initiative isn't properly explored until Lost's second season, their existence and purpose was almost fully-formed from an early stage. The Lost bible makes mention of a "corporate think tank" involved in cutting edge scientific studies, that had built an underground network of stations under the island, and had established a replaying transmission (DHARMA were ultimately revealed as creating the Valenzetti Equation broadcast, rather than the French distress signal).
Despite being unnamed, this is essentially a blueprint for the DHARMA Initiative, and sets the foundations for stories that would echo deep into Lost's fifth and sixth seasons, where the full nature of the experiments was unveiled.
From an early point in its pre-production, Lost identified the need for "home" interior sets that moved the action away from the beach where Oceanic 815 crash-landed. The initial plan was for the group to move inland in season 1 and then, at some point in season 2 or later, have the survivors relocate to the underground bases built by the DHARMA Initiative, and this is more or less how events pan out.
For a brief time, Jack moves some of the remaining passengers to a nearby cave harboring a fresh water source but, following the opening of Desmond's Hatch and the discovery of the Swan station, everyone eventually ends up living underground and making use of the station's relatively homely facilities and supplies.
Sawyer And Juliet
Sawyer's original character description fits Josh Holloway's character perfectly - a tough, unforgiving con man with deeply-rooted Daddy issues. However, his bio also includes a line about a future love interest unlocking the character's softer side. The Lost bible makes clear that this character is intended to be Shannon, although that particular pairing never became a reality. The arc where Sawyer's persona is softened by a meaningful relationship, however, was retained and featured heavily in season 5.
Trapped in the past, Sawyer embarks on a relationship with Juliet, previously a member of the Others. Their romance is a catalyst for huge character development on both sides and Sawyer never quite recovers from watching Juliet die in Lost's season 5 finale.
Jack vs. Locke
The constant rivalry between Jack and Locke was a central tenet of Lost's philosophy, typifying the entire "man of science, man of faith" debate that rumbled on throughout the series. Perhaps unsurprisingly, the seeds of this conflict were sown very early in Lost's conception. Initially, the plan was for the Oceanic survivors to hold an official election which would pit Jack against Locke in a more formal fashion. Ultimately, Lost took a subtler approach with the angle, positioning Jack and Locke as de facto, rather than appointed, leaders that different characters would choose to follow.
In later seasons, Lost's Jack vs. Locke story took on a life of its own, as the latter became possessed by an embodiment of evil known as the Man in Black and Jack took over Jacob's position as protector of the island, elevating their feud to an apocalyptic level.
One potential storyline listed in Lost's original plan was for the main cast to discover a military submarine that they hoped to use as a means of escape, but that would already be under the control of an unspecified enemy group. A version of this storyline plays out in Lost season 3, albeit with significant modifications. A submarine is revealed to be stationed on the island and is under the control of the Others, having first been owned by the DHARMA Initiative. Jack sees the vessel as a potential means of finally leaving the island, but Locke ensures that the sub is destroyed before this can happen, widening the divide between the duo.
Another planned addition to the island's population was the arrival of a lone parachutist that the survivors see eject from a plane and land somewhere on the island, immediately heading out to locate this mystery figure. As with the submarine angle, however, this plot wasn't employed until Lost's third season. When Charles Widmore's freighter was sent to the island to rescue the survivors (among other things), Naomi Dorrit was ordered to act as a scout, parachuting onto the island out of a helicopter.
Just as the outline in the Lost bible suggests, Naomi's arrival cracks open a whole new world for the Oceanic survivors, and heralds an entirely new chapter of the story whereby the main characters are no longer confined to the island itself. At least, not physically speaking.