Michael Hartnett joined the Marines because he wanted to be a tough guy. But deployments to the first Gulf War and Somalia left him haunted by nightmares. He turned to booze; after a bad-conduct discharge he fell into drugs for more than a decade. Three years ago, he convinced a military board to upgrade his discharge. That change in status gave him the chance he needed. Now he's studying to be a social worker so he can help other vets.