The premise of Before I Go to Sleep is quite a good one. A woman wakes up each day with no memory beyond her early twenties; soon she begins to realise that some dark secrets are being hidden from her. It's sort of in similar territory to Christopher Nolan's early neo-noir Memento (2000), which was also a mystery/thriller about a character with a short-term memory loss condition. Like that one, here one of the interesting angles is that the central character has no idea if their friends really are friends or actually enemies. It's true that several aspects of the storyline require you to stretch your belief somewhat; however, many thrillers are similar in this respect, so this wasn't such a deal-breaker for me. The problem I essentially had is that while the idea may be pretty intriguing, ultimately the pay-off is somewhat mediocre and conventional. Piece by piece the puzzle is slowly unravelled but it doesn't end up presenting us with a picture that is very inspired or interesting and you sort of ask yourself 'is that it?'