Millions of pilgrims gather in the valleys outside the city of Mecca in today's Saudi Arabia to take part in the annual five-day pilgrimage every Muslim hopes to complete at least once. Since non-Muslims aren't permitted in Mecca, Feiler's surrogate is Anisa Mehdi, a veteran reporter of the Hajj, who joins a group of Muslim pilgrims from Boston who begin their journey in Medina, the second of Islam's holy cities. The Boston pilgrims follow Muhammad's path, beginning their Hajj by circling the Ka'aba, the ancient shrine at the center of Mecca's Great Mosque. The pilgrims enact the rituals laid out by Muhammad, experiencing exhaustion, injury and elation as they seek forgiveness and inner peace.