Behind the laundromat, where there had always been a plain brick wall, Milo found a little door no taller than he was. He ducked inside. A small clockwork librarian slid a card across the counter. Tiny gears ticked inside her chest. "We lend tomorrows here," she said. "Borrow one good day from your own future and spend it today. Just return it by the deadline on the card."

Milo took the card. Tomorrow was his big science fair, and he wasn't ready. "I want a perfect day," he said. "One where everything goes right." The librarian nodded and stamped the card. Right away his backpack felt lighter and his head felt clear. "Spend it well," she said.

Everything went right all day, which felt strange. Milo aced a quiz he hadn't studied for. He caught a falling glass before it broke. Then he found something odd in his pocket: a second card, blank except for one word. "More," it said.

Milo whispered "more," and the card pulled three extra perfect days from his future all at once. They were wonderful. But then his calendar jumped ahead, and he'd missed his own birthday and two weekends with friends. The good days had cost his favorite days. He learned his lesson the hard way.