Ambition has its price in this political thriller written and directed by acclaimed playwright David Hare, the author of "Plenty" and "The Judas Kiss." Charlotte Rampling, the enigmatic star of "Swimming Pool" (2003), stars as a Tory politician who killsa former associate she suspects of blackmail. When she realizes she was wrong, she not only has to find the real blackmailer but help her victim's daughter find her missing father. In a change of pace from his role as Dumbledore in the "Harry Potter" films, Michael Gambon co-stars as Rampling's husband.