Knock-out prediction

The magician takes two small decks of cards from a card holder, one with a red back and one with a blue back. He places them on the table and explains that they each consist of four kings, two of which are revealed as a prediction. He then asks two spectators to choose a black king and a red king. Once they have chosen, he spreads the cards from both decks on the table, and the only two revealed are the chosen kings!
He continues by covering these two kings and the second surprise is that they have a different color on the back than the other cards they are next to!
Finally, as a third surprise, he turns over the other cards and they are all blank!

• Bicycle cards.
• Simple and shocking.
• The trick is fully automatic.