Demi Moore's toyboy lover Ashton Kutcher, who, according to reports, believes he's lived 6,000 years through reincarnation, stars as Evan Treborn, a college student who finds that particularly traumatic moments in his life have been blanked out of his memory. Total recall being difficult, he enlists the help of a psychologist, who tells him to record difficult moments in a journal. Gradually, the pieces come together.

Later, re-reading the journal, he finds he can regress to those moments and alter the way incidents affect his life and those close to him, such as Kayleigh (Amy Smart), Lenny (Elden Henson) and Tommy (William Lee Scott). A childhood incident altered can affects things markedly in other ways, too.

Is this a psychological thriller in the style of The Sixth Sense, or an attempt to cash in on the popularity of Donnie Darko ?

Darko concentrated on the manipulation of a single incident to create a crucial alteration of the past, much as happens in The Butterfly Effect. Unfortunately, writer/directors Eric Bress and J Mackye Gruber (of Final Destination 2 fame) go alteration crazy.

Evan is constantly going back to change things, in order to achieve a better outcome, and so an effect that seems clever at first, starts to feel tedious. The Bress/Gruber double act takes on weightier topics, such as child abuse, but what it leaves out is a little light humour.

Getting carried away with an idea is one thing, flogging it to death entirely another.