Synopsis: An American businessman in the Balkans decides to while away an afternoon in a curio shop after closing a big deal. He finds most of the goods laughable in quality, and the shop's owner disagreeable.
When he finds an antique, ornately ornamented book, however, he becomes intrigued. He tries to buy the book, entitled Merlin's Diary. At the suggestion, the shopkeeper becomes almost violently opposed, shouting his disapproval of the suggestion. The businessman, however, continues trying to haggle for the book. The shopkeeper presses on with his warnings that the book's magic is too powerful for it to leave his shop.
Though the businessman scoffs at the idea, he is soon transported by the book back in time by it. He finds himself in the presence of the book's author, Merlin.
Now in front of the great wizard, the businessman still argues that magic does not exist. Merlin merely laughs at the businessman's disbelief, marking him with a minor spell that will convince the man that there are things greater than he can see operating in the universe. Merlin then sends him forward in time to the shop. There, he remembers his encounter with Merlin more as a dream than reality. Shaking it off, he resumes trying to haggle for the book. The shopkeeper is still firmly opposed to selling it. In the renewed exchange for the book, the businessman discovers the mark Merlin left on him: he now has white hair. Taken aback, the businessman hastily leaves the shop to ponder whether magic exists—not to mention the encounter with Merlin—was a dream or reality.
After he leaves the shop, the shopkeeper chastises himself for leaving his diary lying about where any mortal could discover it. The modern day Balkan shopkeeper was, in fact, Merlin all along.
Notes: This story is signed, "S. Ditko". It's unknown whether that accounts for story and art, so Steve Ditko is listed here as an unconfirmed creator for writer, as well.