Kevin, who is on a dangerous path of despair, returns to his childhood home in Texas to crash with his widowed twin sister, Amy, and teenaged niece, Reese. It is a strained homecoming - he and his family have grown apart over the years - and Kevin has no real hope that anything will get better. But a series of fantastic events, including a meteorite landing near the house, lead Kevin to meet an unlikely celestial guide, Yvette. Yvette delivers incredible news to Kevin: in every generation there are 36 righteous souls on Earth whose mere existence protects the world. Kevin, she tells him, is the last of the 36 righteous. Humanity has been thrown into crisis. Without the 36, the world will begin to lose the one thing that allows us to persevere through the ups and downs of life: hope.