"Vanished into thin air" is an oft-used phrase to describe how people disappear suddenly and completely. "Gone" accomplishes the same thing, albeit in a more succinct, abrupt way, and provides Investigation Discovery with perfect true-crime fodder. The network introduces the hourlong series thusly: "No shoes in the hall. No coffee in the pot. He was supposed to come in late, but when she woke that morning he was just gone. As the day went on, her unanswered calls grew more frantic, and her unease became panic. Something was wrong but the truth is even darker than it looks." What follows are stories of missing people who leave a trail of secrets -- and distraught loved ones with mysterious pasts -- in their wake.