This is an Impromptu “Any Card At Any Number” Card Magic effect that the illusionist is always able to perform, even with an incomplete and borrowed deck, and the most incredible thing is that he will never touch the deck of cards but will simply give all the instructions to the spectator!

After freely shuffling a deck and secretly taking a small group of cards from the center, so that the magician does not even know how many cards it will now consist of, the spectator will choose a CARD, which then he will lost following a free procedure suggested to him.
Having randomly cut the deck into four separate parts, he will secretly count the cards in one of them by remembering its NUMBER and, after shuffling both the top and bottom of the deck, reassemble it and then divide it into three parts again and complete the cut.
At that point, the magician will invite him to turn and stack the cards one by one face up on the table, thinking of both his CARD and NUMBER and mentally counting, but never saying anything, trying not to betray his thoughts.
As soon as the illusionist tells him to stop, the spectator will confirm that he has already gone over his number but probably also that he has not yet seen his chosen card pass.
In any case, he will turn over the newly stacked group of cards, placing them under the rest of the deck, always held face down.
Only then, he will first announce his own secret NUMBER and, counting the cards from the top of the deck, he will hold in his hand the card found at the chosen NUMBER. Having also revealed aloud the identity of his CARD, he will magically find it in his own hands!