A Ghost Card Escapes From Its Restraint

Whether you like ghost stories or escapes from bondage, I have a demonstration that might appeal to you.
The magician shows three cards - two depicting a haunted house, and one of a ghost.
The three cards, ghost in the centre, are attached securely to a key-chain.
Magically, the ghost escapes from the key-chain, and is found elsewhere. The question would be: How can a card, any card, vanish from between two others while they remain in full view? I'll bet you can solve the riddle.