The Serpentine Assassin is the second of the short series of fast-paced, action-based adventure of Agent 13: The Midnight Avenger, written by Flint Dille and David Marconi in a style reminiscent of popular 1930s pulps. It picked up directly from the story where the previous book, The Invisible Empire, ended. The eponymous title referred to Agent 13, brainwashed after he was captured by the Brotherhood, though it had appeared to his ally, Maggie Darr, that he drowned in the icy Atlantic waters. Source: Wikipedia (en)