A writer (McGregor) is hired to pen the memoirs of ex-British prime minister Adam Lang (Brosnan), staying on a remote stretch of Martha's Vineyard in New England where Lang is based.
The more he delves into Lang's life the more uncomfortable he becomes and stumbles onto a mystery surrounding the death of the ghostwriter before him.
Roman Polanski's impressive tale of political paranoia features a spot-on performance by Pierce Brosnan as (don't say Tony) a British PM embroiled in a scandal about events that occurred when he was in office.
The film, based on a novel by Robert Harris, twists and turns with knowing slyness, unfolding at a pace that both entrances the viewer and allows the story to develop quite perfectly.
It's both provocative and witty and a welcome style of movie amidst the 3D, animation and special effects that are dominating the screens. It's not that I don't love a mindless blockbuster, it's just that it's great to see a proper thriller.
Of course, the film itself has rather been overshadowed by 76-year-old Polanski's arrest in Switzerland, but in truth The Ghost should be celebrated as a crackingly entertaining movie.
The ghostwriter, played with an engaging charm by Ewan McGregor, is only ever referred to as the Ghost. And while they might imply a shadowy figure, this Ghost is an intelligent but ordinary man who finds himself in an extraordinary situation.
Arriving on the misty and beautiful Martha's Vineyard, McGregor is charmed by his host, though a little concerned about the death of the writer originally hired to pen the former PM's autobiography.
And things get worse when Lang is accused of illegally holding suspected terrorists in Pakistan and turning them over to the CIA to be tortured.
Secret photos and documents aren't the only things the Ghost has to deal with, as Lang's wife Ruth (don't say Cherie) starts to show an interest in him.
Kim Cattrall also makes a real impact, playing Amelia Bly, Lang's fiercely loyal chief of staff who knows all the darker truths behind his time at No 10. Apparently she "spoke with" someone at Gordon Brown's office to help her understand the role.
With Brosnan excellent as the PM and Olivia Williams perfect as his wife, it's a film that is both amusing and unnerving. And that's a rare trick.
The Ghost is a wonderfully atmospheric conspiracy thriller. Impressively intelligent entertainment.