Horror Express, a 1972 Spanish-British horror science-fiction film directed by Eugenio Martín, unfolds aboard a Trans-Siberian Express returning from Moscow to Spain. A frozen caveman discovered in a Siberian cave is thawed on the train and revealed to be an ancient alien life-form that can possess human hosts and spread through touch, turning passengers into suspects and victims. The claustrophobic setting, practical effects, and the lively clash between Peter Cushing’s scholar and Christopher Lee’s villainous schemer give the movie its distinctive old-school charm. While modest in budget, it blends Gothic mood with pulpy thrills, delivering memorable set-pieces and shocks rather than gore. Over the years it has become a beloved cult classic among fans of Hammer-era horror for its confident performances, atmospheric train-haunted tension, and the undeniable screen chemistry between its two horror legends.