Reese Witherspoon plays ambitious medical intern Elizabeth, who regularly clocks in 20 hour days at the hospital. Her work is her life, much to the chagrin of her sister Abby, who is married, with kids, and constantly attempting to get Elizabeth to go out more. When Abby finally succeeds in setting up a blind date for her sister, Elizabeth has an accident en route while driving to meet the mystery man, and the stage is set for love. David (Mark Ruffalo) has been apathetically searching for a new apartment in the cutthroat San Francisco housing market, while attempting to overcome his wife's death two years ago. When he finally finds the perfect place, nothing is going to make him leave, and this includes the blonde control freak (Elizabeth) who suddenly shows up while he's busy vegetating. She claims the apartment is hers, and it becomes ever clearer that Elizabeth doesn't remember her past, and shows irrefutable signs of being a ghost...