Pvt. Johnnie Stevenson cleaned his truck one last time, scraping off the barnacle-like mud and pulling crushed water bottles from under seats. But deployment to Afghanistan was almost over, and his thoughts drifted elsewhere. Was his pregnant fiancée ready to be a mother? Facebook provided so few clues. Nor could it answer him this: Was he ready to be a father?

Capt. Adrian Bonenberger made plans for his final patrol to Imam Sahib. But inside, he was sweating the details of a different mission: going home. Which soldiers would drive drunk, get into fights or struggle with emotional demons, he wondered. What would it take to keep them safe in America?

Sgt. Brian Keith boarded the plane home feeling a strange dread. His wife wanted a divorce and had moved away, taking their son and most of their bank account with her. At the end of his flight lay an empty apartment and the blank slate of a new life.

“A lot of people were excited about coming home,” Sergeant Keith said. “Me, I just sat there and I wondered: What am I coming back to?”