Every year an estimated 210,000 people go missing. The majority return safe and sound with in 72 hours. Thousands do not. In the days, weeks, months or years that follow, the families left behind wait in limbo. The missing disappear into the ether, what remains is hope, that some day there might be a knock at the door, a phone call, a sighting, just a sign of life or a clue to the mystery.