In 2004, Morton starred as a love interest in the dystopian film "Code 46", directed by Michael Winterbottom and alongside Tim Robbins, and played the wife of a man who witnessed a deadly accident in the drama "Enduring Love", opposite Rhys Ifans and Daniel Craig. Critics were polarized for the latter film and suggested that Morton did not have enough time on screen. Nevertheless, she earned a nomination for the Best Supporting Award at the 2004 British Independent Film Awards. In "River Queen" (2005), she took on the role of a young Irish woman finding herself on both sides of the wars between British and Maori during the British colonisation of New Zealand. The film was a box office success at the New Zealand box office, grossing around NZ$1 million in the country. For her role, she received a nomination for the New Zealand Screen Award for Best Leading Actress. She starred alongside Johnny Depp in the little-seen period drama "The Libertine", and appeared in the drama "Lassie", both of which were also released in 2005.