"The Empty Drum" is a short story by Russian writer Leo Tolstoy. A man took a woman for his wife that the king of the country had an eye on. So the king decided to overwork the man till he died so he could then marry his wife.
But each time the man completed his task on time. Even when the tasks were impossible like building a cathedral in a day or a river with ships in it by nightfall his wife assured him it would be done and it was as she said. But then the King came up with an extraordinary task. He asked the man to, "go there, don't know where and bring that, don't know what"...