He's Gone

Rachel and Luke Hemmings graduate college together and have been dating for 4 years. They are madly in love with eachother and never want to leave one another, but that doesn't mean they might need to leave eachother.
Luke has been called upon to enter the United States Army for a year and a half. He eventually decides to go but he doesn't want to leave Rachel. She is what he lives for and he wants her to be happy, but he feels the need to enter the army. 
When Luke leaves, will Rachel be able to handle her other half being across the world? Will she be able to handle the loneliness? Will she be able to handle him being gone?