That doesn't hurt. Viewers are likely to be drawn to the film by the presence of Grant, Hackman and Sarah Jessica Parker, but they are apt to be really drawn into the story because of the work of director Michael Apted. But the homeless man's death makes no sense. Then all records of the man and his medical history start vanishing. The film reaches cruising speed quickly, with dialogue peppered with the offhand humor for which Grant is noted.
Puzzle pieces turn up with increasing speed.
If Guy's curiosity wasn't sufficient motive, he faces the loss of his entire promising career as he pursues the mystery to the point of placing his own life on the line. There's a climactic confrontation spiced with strong suspense. The issues sort themselves out quite quickly at the end, but the film doesn't leave viewers with an unsatisfied feeling.