Take an ordinary deck of cards and memorize the bottom card. Before you start the trick turn the bottom card upside down and place it back on the bottom of the deck. Give the top half of the deck to a spectator and keep the bottom half for yourself. Tell them you will remove one card from the deck you are holding and do so. Look at the card but do not memorize it, the card you need to remember the bottom one. Place it on the table in front of you. Tell them to remove one card from their deck but do not let you see. When they do this put the hand with the deck in down to your side and when no one looking just let flip the deck over. When the spectator has removed one card and looked at it. Tell him to place it on the table face down next to yours. Now tell him to put your card face down in his deck without looking, that way it is lost and no one knows what it was. Now take his card and place it in your deck face down so that it is the only card, except for your card, that is face down. Now take half of his deck and turn it face up and lace it on the top of you deck. Take the other half of his deck and place it face up on the bottom of your deck. Now tell him that the deck should be face up, face down, face up. He will naturally agree. Show him that all the cards are face up except two. Turn over your card and ask him what he had. He will tell you and then turn over his card.