Three women walk into a post office. No, this isn't the beginning of a joke. It's the beginning of a hostage situation.

On an ordinary spring afternoon in a small-town post office, a domestic dispute spirals out of control. The husband pulls a gun and barricades himself inside with four hostages—his wife, a young woman searching for her purpose in this world, a midlife mom facing her only daughter's graduation and imminent departure, and an elderly woman hiding a secret about her life at home. Outside, even the negotiator is forced to put aside her own personal baggage in order to find a peaceful resolution to a volatile situation . . . using exclusively words.

Each of the three women who walked into the post office is carrying something that, if mailed, would profoundly change her life. Through the course of the daylong siege, these strangers will forge unforeseen bonds and reveal things to each other they haven't even told those closest to them. And none of them will ever be the same.