In this article, the author reveals the secret behind a seemingly impossible card trick. The trick involves a magician correctly guessing the chosen card from a shuffled deck. The explanation lies in a principle known as the "Gilbreath Shuffle," which alternates between red and black cards. By manipulating this order during the shuffle, the magician can use a secret marking system to infer the chosen card. The trick is thus not as inexplicable as it initially appears.