A multi-phase color changing deck and box routine.
The magician removes a blue deck from a blue box. A spectator chooses any card from the blue deck The freely chosen card is shown to be the only red-backed card in the blue deck.
The blue deck then transforms into a red deck of cards.
The selected card changes into the only blue backed card in the red deck.
This blue card is left on the table.
The magician asks the spectator to pick another selection from the new red backed deck. The cards is lost into the deck. He pretends that this red selection will also transform into a blue card... but no blue card is found in the red deck. The blue card placed on the table from the beginning is found to be the second selection!
The red cards are placed inside the blue box.
For the grand finale, the blue box changes into a red box!