After the worst happened, Boston was at its best. A series of perfect strangers provided life saving and life sustaining assistance to spectators and runners in need. From a shirt ripped off to be used as a tourniquet for the critically wounded, to a sweater, phone call, or just a hug for the cold, lost and scared. Over 40 spectators, runners and first responders share their stories of the moments of grace that not only saved lives, but created unbreakable bonds.