BY their very nature, most whodunnits rely on the central idea that you find out who the murderer is at the end.

If you do not discover how and why the victim was killed then the story is likely to be unsatisfactory and if the culprit is revealed too early then what is the point of carrying on? The case is closed.

But that is where Gone Girl comes in.

Gillian Flynn's novel turns almost every convention of murder mystery writing on its head and in the saturated crime and mystery genres that is probably why it is so well loved.

The author has turned screenwriter for this film adaptation by David Fincher in which you actually find out who the culprit is about half way through.

And it is somehow better and more compelling for it as your opinions on certain characters and attention regarding certain events suddenly shifts.

Gone Girl focuses on Nick and Amy Dunne (Ben Affleck and Rosamund Pike) whose relationship is fizzling out after a whirlwind romance.

Then when Amy disappears the spotlight is turned on Nick as prime suspect.

The film has many twists and turns and has a lot to say about the moral blackhole that exists in the media scrum every time a crime shocks a nation.

If you have read the book you will not get as much out of it as you know what is coming.

But Fincher's directing style is slick, engaging and well paced with vivid flashbacks.