Dear John is a movie for women, that is for sure. A man comes home and meets a girl. He is home from leave visiting his father. His father is rather odd which you later learn that he has a disability of sorts. The one thing he and his father enjoy as it's just them is collecting coins. The father spends most of the movie cleaning them.
He starts to get to know this girl who intrigues him. He learns how good she is with kids as one of her good friends who had just lost his wife hangs around her with his little boy. However, the soldier gets deployed. They vow to write to one another and make this blooming relationship that they have work. They do write to one another. It seems to be working. The letters are long and they are consistent. It makes his days.
The deployment time is over, but the group stands together. They are asked to stay longer. They are asked to extend their time overseas. The commander of this tells the group that this is a group decision. They are either all in or not. They all decide that this is best. The soldier is allowed only a short time to come home and he comes to see the woman that he loves. Things seem to be going good until he gets the letter than every soldier hates. It's the letter that tells him that she is no longer to be with him. She has found someone else. He dumps everything and has to learn how to let go of his anger and move on. He does this until other things happen.
He learns that his father passes away. This rocks the soldier's world. It just doesn't seem right. He sees the woman who he used to love. She is with someone he would have never dreamed of her being with. The only reason that she is with him is because the father is deathly ill with cancer and they needed the insurance and the husband needed someone to entrust his son to.