On the day he planned to make his sacred journey, or hijra, to the Islamic State, 19-year-old Mohammed Hamzah Khan woke up before dawn at his house in the Chicago suburb of Bolingbrook, Illinois, and walked to the nearby mosque to pray. It was Saturday, October 4th, 2014, an unusually cold morning, though Hamzah, a slender young man with a trimmed black beard, was dressed for warmer weather in jeans, boots and a gray sweatshirt. By sunset, he'd be gone for good: leaving his parents, his friends, his country and all he knew for an unknown future in the "blessed land of Shaam," as he called Syria. He would be taking his teenage brother and sister with him. Allahu Akbar, he prayed with the men in his family, and tried to banish his doubts: "God is great."