First, I'd like to say that I am sick and tired of reading reviews from people who don't apply their brains to interpret a movie, who watch a movie expecting a cliched Hollywood plot that has been rehashed over and over. Is it so hard to appreciate a movie that is different? Does every movie have to have a huge exploding climax and a fairy-tale ending? Don't you suppose some things in life don't work out that way? I appreciate this movie for telling a story that is different - it's so sad that people are so narrow-minded. *rant over*
Okay, here is my interpretation of the film, since legions of people have reviewed this film not understanding it. It is my interpretation, and since I have not read the book on which this story is based - it is therefore not necessarily accurate.
The Eye is hired to watch Joanna, and he is supposed to catch her in something. During which, the Eye sees a physical likeness of her to his daughter whom he lost when his wife left him. While he tails Joanna, he learns her sad story of how she lost her father and this triggers some sort of psychological connection with her - since he lost her daughter.
Joanna meets a blind rich man named Leonard, and because he can't see her and therefore she feels that he can't see her phoniness and is not attracted to the phony image she portrays when others fall in lust with her, she trusts him inherently and eventually falls in love with him. She proposes to him, and he accepts.
At this point, one is not sure whether the Eye is in love with Joanna since his hallucination of his daughter asks if he is jealous to which he affirms. Nevertheless, the Eye tries to stop them from getting married and inadvertently causes them to have a car accident and Leonard dies.
Joanna goes on the run again, and checks into a hotel. A detective who has been following her enters her hotel room, and she shoots him and runs off hurriedly. The Eye manages to extract a pubic hair from the bathtub and finds out her real name. The Eye then goes to a correction facility where Joanna used to go as a young girl and meets Dr Jeanne who explains her past, and that she taught Joanna some of her survival skills.
Joanna's car breaks down and she gets picked up by Gary and they stay over at a motel. Gary tries to get her on drugs but she refuses and Gary gets violent on her, kicking her and killing Leonard's child which was growing inside her. The Eye comes into save her, but as he gets rid of Gary, he goes back to the motel and finds Joanna has run off again.
With the help of Hilary, the Eye tracks Joanna down at a hospital and learns that Joanna lost her baby. While she is sleeping, he puts on his wife's wedding ring on her finger - which of course implies that he sees his wife's likeness in Joanna.
Joanna learns that someone was tracking her and helping her, and almost catches the Eye as he was tailing her. She gets surrounded by police who have tracked her down - and the Eye risks his life to let her get away. Joanna flees to Alaska and finally the Eye meets Joanna face to face although Joanna doesn't know yet that the Eye is her "guardian angel". The police use Dr Jeanne to try and identify Joanna when they track her down to the diner where Joanna works - but Dr Jeanne refuses to divulge Joanna. The Eye once again rescues her, by asking her to flee in his car.
When they are in the Eye's trailer, it dawns on her that the Eye is her guardian angel, and she is so scared she shoots the Eye with the gun that the Eye already set up for her to use (containing blanks). She drives off in his car, and he chases her on a motorbike. She crashes and he pulls her out of the car, and finally Joanna comes to accept her guardian's true identity - having remembered all the times where she saw his face briefly.
At this point, it is implied that they get together - but it is all left to your imagination. The Eye feels that he has redeemed himself, by watching over Joanna, chasing her and finally getting her to accept him (redeeming him from his feeling of failure over losing his wife and daughter, and his inability to track them down) - and Joanna meets her guardian angel - a protective fatherly figure who accepts her for who she is.