From Netflix:

After surviving a brutal assault, Christine Lucas awakens each morning incapable of remembering anything about her past, including the previous day. Little by little, however, she begins to suspect that her husband played a role in her misfortune.

Remember the 2000 film “Momento” with Guy Pearce? “Before I Go To Sleep” reminds me of that film because it is basically a film about memory and amnesia. In addition the film is basically a mystery story that initially does not seem to be a mystery. Details are not that hard to follow (“Momento” was notoriously difficult, causing much discussion) if somewhat implausible. If Christine had to begin all over each day, I am not sure she would have the time through the accumulation of days to really accomplish what she did.

While not a great film, nonetheless Nicole Kidman, Colin Firth, and Mark Strong give good performances. Mark Strong played Stewart Menzies in “The Imitation Game”.

Not at all a waste of time.