At the beginning of the 20th century American Doctor, Duncan MacDougall, engaged in a series of unethical experiments. Those experiments concluded that should one suffer a death not ordained by fate the human body lightened by an average of 21 grams, the weight of a man's soul stone. Today, two men, Sakarai and Amano, are in the hunt to find people who are about to die before their time and either prevent their unnatural death or recover these stones, "Livingstones."