Highlander II: The Quickening is a 1991 science fiction film directed by Russell Mulcahy and starring Christopher Lambert, Virginia Madsen, Michael Ironside and Sean Connery. It is a sequel to the 1986 fantasy film Highlander. Set in the year 2024, Connor MacLeod regains his youth and immortality and sets out to free Earth from the corrupt operators of an artificial ozone layer.

The film was released on 12 April 1991 in the United Kingdom and on 1 November in the United States. Most of the filming was done in Argentina amid the country's economic woes, leading to the movie's investors and completion bond company taking over production. The resulting film was panned by critics and fans and is considered to be one of the worst films ever made. The following film, Highlander III: The Sorcerer, ignores the events of Highlander II. Several cuts have since been made to address plot inconsistencies and special effects.

Five hundred years ago on the planet Zeist, sorcerer Juan Sánchez-Villalobos Ramírez leads a rebellion against the corrupt leadership of General Katana. Using the Quickening, he creates a bond with fellow rebel Connor MacLeod that even death cannot break. Katana and his troops crush the rebellion and put Ramírez and MacLeod on trial. They are banished to Earth to live as immortals, where they fight each other until only one survives. The winner faces a choice to remain on Earth as a mortal or return to Zeist with their crimes forgiven.

By 1999, Earth is devastated by industrial pollution and a damaged ozone layer. Millions die, including Connor's wife Brenda Wyatt MacLeod. No longer immortal, Connor supervises a scientific team headed by Dr. Allan Neyman which creates an electromagnetic shield. Earth is protected from radiation but shrouded in darkness, heat, and humidity. In 2024, the Shield Corporation is run by David Blake, and it imposes heavy fees on countries for continued protection.

An elderly Connor is approached by Louise Marcus, the leader of an anti-shield group. They believe the ozone layer has recovered, and the Shield Corporation is lying about it to maintain their revenue. Connor refuses her request for help because he is too old and disapproves of her group's methods.

Katana sends two immortal assassins to kill Connor, to prevent his return to Zeist. Connor decapitates them and the quickening restores his youth. Before making love to Louise, Connor calls out for his former mentor. Ramírez appears where he died in Glencoe, Scotland, briefly interrupting a performance of Hamlet. Finding his way to Connor and Louise, and the trio devise a plan to destroy the shield.

Katana arrives on Earth and makes an uneasy alliance with Blake in exchange for Connor's head. Blake imprisons Dr. Neyman. Connor, Ramírez, and Louise break into the prison and are led into a trap. Ramírez sacrifices himself to save Connor and Louise. Connor and Katana duel. When Connor beheads Katana, he uses the quickening energy to destroy the shield. As the world returns to normal, Connor asks Louise to come with him to Zeist.

Steven Grives and Jimmy Murray portray characters playing Hamlet and Horatio respectively in the scene where Ramírez is resurrected.