On a fated flight, a balloonist makes a discovery that changes her life forever. A telegraph operator finds an unexpected companion in the middle of the Amazon. A doctor is beset by seizures, in which he is possessed by a second, perhaps better, version of himself. And in Regency London, a bare-knuckle fighter prepares to face his most fearsome opponent, while a young mother seeks a miraculous cure for her ailing son. A collection of interlacing tales from the author of "The Winter Soldier".