movie spoiler: (highlight the following paragraph to read)
In a nutshell, Lucy (Drew Barrymore) is suffering from a form of amnesia called Goldfield syndrome where every night as she sleeps her brain sort of reboots and all her short term memory is lost. As a result she can't remember anything since the day before her accident an year ago. Harry(Adam), falls for Lucy has to make her fall in love with him daily as she can't remember him the day after. While goldfield syndrome is really fictional (you wouldn't think so unless you studied neurology), its not total fiction. For example there is another patient who can only remember 10 seconds -- seems like fiction? read on...
I knew very little about amnesia, so I did some research on the subject and found some fascinating stuff. For example in a form of amnesia called Anterograde amnesia, one can indeed forget things within a few seconds to few minutes, hours or days, much like in goldsfield syndrome.
One such extreme real case is the man with a "7 second memory!". There is a documentary film on this, which I hope to find somewhere on the net.
Another interesting book, that I'm keen on reading is, "The Man Who Mistook His Wife for a Hat", which has several accounts of patients suffering from loss of short term memory.
The brain is an awesome machine, and a mystery that's worth trying to understand - both biologically and spiritually.