Three A.M., a few nights before Christmas, 2004. The war in Iraq is approaching its second anniversary, and the conflict in Afghanistan is into year four. A soldier sits in a small suburban house. He is a baby-faced 21-year-old but has a look of exhaustion that can’t be concealed. He should feel safe here. But the young man has lost his ability to reason. He closes his eyes as if to tune out the chatter from the other people in the room, and when he opens them, he snaps. “The hajjis are coming!” he screams. “The hajjis are coming!”

To those around him it’s clear that Army Specialist Andrew Velez has been sucked into some dark corner of his mind. “They’re coming!” he repeats. “They’re coming!” Andrew stands up and runs around the house, turning off all the lights. A young woman is standing nearby, and Andrew ushers her into a bedroom, hollering at her to duck for cover. He drops to the floor and slides across the room on his stomach. At some point he produces a rifle, albeit an imaginary one, and squeezes the invisible trigger. “I’m not gonna die!” he shouts. “I’m not gonna die!” Then Andrew runs for the back door. The woman chases him. When she steps outside, Andrew pulls her to the ground to protect her from enemy fire. “I’m not gonna die!” he screams. “I’m coming home to see my babies!”

But Andrew Velez is home. He’s at his in-laws’ house in Lubbock, Texas. There are no hajjis here, no gunshots or shelling, and his babies sleep soundly nearby. The young woman is his wife and the mother of his children. Her name is Veronica, and she patiently explains as much to Andrew, even as he continues to scream and shoot at an imaginary enemy. Someone calls the police. Veronica phones her father-in-law, Roy Velez, who arrives 15 minutes later, gets out of his truck, and hugs his son. Roy, an ex-cop who’s built like a bear, has detained his share of criminals, but he doesn’t have the strength to keep Andrew still, so he lets him flail. The police show up, then leave after Andrew calms down.

Andrew has an older sister, Monica, who is now a psychology student and has worked with assault victims. In the days after Andrew’s episode, Monica asks her brother to try to remember everything he can about the incident. She suspects post-traumatic stress disorder (PTSD). Besides afflicting those who have experienced combat—or other violence, like assaults or accidents—PTSD often affects people who have seen dead bodies. So Monica prods Andrew, and Andrew cooperates as best he can. “I remember being on the ground and looking up and seeing the police standing over me,” he tells her. She reminds him that the police didn’t show up until the end of his fit of paranoia. She talks to him about PTSD triggers and asks him to think about what might have prompted his behavior. There is an image, he tells her—something he just can’t shake. “I remember closing my eyes,” he finally says. “I remember closing my eyes and seeing Freddy.”