The most-respected sequel ever made. The film that ended on its hero's defeat — and changed what blockbuster sequels were allowed to do.
Three years after the destruction of the first Death Star. The Rebel Alliance has established a base on the ice planet Hoth. Imperial probe droids locate the base and the Empire mounts a ground assault. The Rebels evacuate. Luke Skywalker, at Obi-Wan Kenobi's posthumous direction, travels to the swamp planet Dagobah to be trained by the ancient Jedi Master Yoda. Han Solo, Leia Organa, Chewbacca, and C-3PO flee in the Millennium Falcon and end up at Cloud City, where Han's old friend Lando Calrissian's hospitality turns out to be an Imperial trap.
Luke senses his friends are in danger and abandons his training to rescue them. The film's third act — the carbon-freezing of Han Solo, the duel between Luke and Darth Vader, the reveal that Vader is Luke's father — is the film's structural argument. The film closes with Han frozen in carbonite and en route to Tatooine, Luke with a prosthetic hand replacing the one Vader severed, and the Rebels in continued retreat.
Almost every commercial sequel before The Empire Strikes Back ended in triumph. Empire ends with the protagonists in retreat, their leader frozen in carbonite, their other leader missing a hand, their existential threat unresolved. The film was, in 1980, structurally unprecedented for a major studio release. Most observers expected it to fail at the box office on those grounds. It grossed $538m on a $33m budget and is widely considered the most-respected sequel in the history of mainstream cinema.
What the film established — and what almost every subsequent ambitious sequel has been measuring itself against — is that a middle film in a planned trilogy can end on a dramatic low without alienating the audience. The structural permission this granted has shaped everything from The Two Towers to The Dark Knight to Avengers: Infinity War.
The screenplay was written primarily by Lawrence Kasdan (who that same year was working on Raiders of the Lost Ark) and Leigh Brackett, from George Lucas's story. Brackett, a long-time science-fiction novelist and the original screenwriter on The Big Sleep (1946), died of cancer before the screenplay was fully completed; Kasdan was brought in to finish.
The screenplay is, on close inspection, structurally more disciplined than either of the surrounding Star Wars films. Each main character has a parallel arc — Luke is being trained in self-mastery, Han is failing to commit to Leia, Leia is recognising her own feelings, even Lando is being forced to choose between collaboration and resistance. The arcs converge at Cloud City in a way that no Star Wars film before or since has managed at this level of structural cleanliness.
The Darth Vader paternity reveal is, by some surveys, the most-discussed plot twist in mainstream American cinema. The scene was shot with the on-set actor (David Prowse) delivering different dialogue — 'Obi-Wan killed your father' — to prevent leaks. James Earl Jones recorded the final line in post-production. The cast and crew did not learn of the actual reveal until the film's premiere.
What makes the reveal land is that the film has, structurally, prepared for it. Luke's Force training has progressively suggested that his anger and impulsiveness link him to the dark side. The film's identification of Vader as the dark side's principal manifestation creates the parallel; the reveal that Vader is also Luke's father literalises it. The reveal is one of the few film twists where the structural foreshadowing makes the surprise feel earned rather than imposed.