Jamie (Jake Gyllenhaal) gets the job of a drug representative thanks to his brother. While on the job he meets Maggie (Anne Hathaway) a charming young girl he falls first in lust, and, then in love with. The twist in the tale is that she's suffering from early onset Parkinson's while he's struggling to get his career on track.

Will he marry someone who might not even be the same person some time from now?