The movie begins with some teenagers jumping off bridges. They apparently take pictures of bridges during the day, and at night, around 2 am, they jump off those bridges. The exercise proves to be dangerous and there is a level-headed teenager among them who tries to put some sense into them.
As the movie progresses, we learn that something is wrong with Zack Nelson. He is more aggressive at jumping off the bridges; he no longer gets along with his best friend, and is not getting along with his family either.
His father, Frank Nelson, is the high school math teacher. We notice and they talk about that there are pictures of certain members of the family missing. Frank tries to connect with Zack and tells him he as well is very moved by what happened in the family.
There is some conflict with Zack and his older brother. Apparently Zack fells that his older brother is not at all upset about the death of their mother.
We learn that the mother was suffering from depression and no matter how much therapy she underwent, the sorrow could not be erased and she went into the garage, locked the doors, and killed herself by letting the car run in the locked up garage.
We are shown some tender moments between Frank and his wife, but you get to see that it is strenuous. Whatever was bothering her was so deep that no matter how Frank tried to reach her, he couldn't.
As the movie progresses, we learn that the tragedy that was causing Mrs. Nelson's depression (I don't remember her name) was the death of her daughter. Apparently, Zack (I am a bit murky in the details here) was to watch her, but he was too busy playing basketball, and she ran into the street and was run over by a car.
Zack feels guilty over his sister's death and his mother's death. Frank offers to send him to a psychiatrist, which Zack refuses. (We saw that scene in the promo.)
In another scene as Frank is teaching, he is overwhelmed with sorrow and breaks down in the bathroom. (A very heart-wrenching scene.) We also get to witness Frank's loneliness. He is invited to an adult Halloween party, wherein everyone has a partner, but him. At that party, he gets a phone call, Zack jumped off a bridge and may have drowned.
Now, here's where the movie is ambiguous. We see Frank and his older son in the hospital, and we don't know whether Zack makes it or not. The next scene shows him playing with his friends, but it is done in such a way that you can interpret it as if it is Zack's ghost and his friends are remembering him or he did make it and is happily playing with friends.
This is the story to the best of my memory. I loved the movie, but I was confused by the way it ended. I am hoping that once I watch the DVD, I'll get a better sense of what was going on.