On August 21, 2015, Ayoub al-Khazzani boarded the 15:17 train in Brussels, bound for Paris. Khazzani's mission was clear: he had an AK-47, a pistol, a box cutter, and enough ammunition to obliterate every passenger on the crowded train. Slipping into the bathroom in secret, he armed his weapons and prepared to launch his attack. But when he emerged, he encountered something he hadn't anticipated: three Americans who refused to give in to fear. Anthony Sadler, Alek Skarlatos, and Spencer Stone were childhood friends, taking a vacation together. They had some relevant training: Stone was a martial arts enthusiast and Airman First Class in the US Air Force; Skarlatos was an active duty member of the Oregon National Guard; and not one of the three was afraid of a fight. But their decision--to charge the gunman, then overpower him even as he turned first his gun, then his knife, on Stone--would never have happened if they hadn't had a lifetime of trust, support, and loyalty between them. The 15:17 to Paris is an amazing true story of unparalleled, unexpected courage, and people coming together against fear rather than splitting apart. It is a story of near tragedy averted by three young men who found the heroic unity and strength inside themselves that we all aspire to.