I gazed at the door to Thor's house, waiting for him to appear. It had been years since the heady days of our power. Now, like most of the Norse gods, I'd resigned myself to whiling away the years until Ragnarök. To pass the time, I kept abreast of happenings in human society. As a result, I happened to know that today was April Fool's Day.
       I don't know what inspired me to create a paper-mâché version of Thor's hammer Mjölnir and swap it for the real thing. I told myself it was because I wanted to see Thor humiliated. If things worked according to plan, he'd think he'd recovered the strength of the old days--a falsehood since, like all else on the world, we had both suffered the ravages of age, albeit incredibly slowly. Sooner or later, he'd realize his mistake. I planned to be around to savor that moment.
       The front door creaked on its hinges, and Thor stepped out into the sunlight. The fake Mjölnir dangled from his right hand. I hadn't seen him for a while--long enough to forget the way his muscles moved like living creatures under his skin.
       What if he got really mad? Maybe this wasn't such a good idea . . .
       If I let my trepidation show, Thor would know something was up. "Good morning to you, Lord of Thunder." I bowed mockingly. "Have you been working out? You look as though you could swing that hammer right round your head without breaking a sweat."
       "Hey, Loki." Thor grinned with unfeigned congeniality as though he'd forgotten all the bad blood between us. "I feel as though I might, today."
       He swung the hammer in a graceful arc, then lunged forward. The hammer's head stopped inches from my head. "Since Mjölnir feels so light, perhaps I should pay the giants a visit."
       I licked suddenly dry lips. Much as Thor and I had our disagreements over the years, I didn't really want to see him come to harm. I thought of Odin's wrath should the worst happen and squirmed uncomfortably. I'd have to talk him out of it. "Why stir up trouble?"
       "Don't fear on my behalf, little one." Thor beamed at me.
       I stiffened. I hated it when he spoke in that condescending tone like I was a kid brother tagging along after his elders.
       I had to stop this. But how? "I'd love to join you, but I have errands elsewhere."
       Was that an expression of disappointment flitting across Thor's face?
       I didn't wait to find out.
       Half an hour later, I was chatting up the head giant. Never the brightest star in the firmament, he had to be handled carefully. Too direct an approach, and he'd be suspicious. But if I proved too cryptic, he'd think I was mocking him. I'd learned from experience that it's unwise to anger someone much larger than you. "I hear Thor's been working out," I said.
       "Thor." The giant grimaced, rendering his face even less appealing. "He is a mosquito! A thorn in my side! A gnat--"
       "He's headed this way. Perhaps a retreat would be wise. You know how your troops wilt in the midday heat."
       "True. But to turn and run--"
       "Discretion is often the better part of valor."
       "Too late for that." The giant pointed southward, and I saw Thor's goat cart approaching.
       I was out of time!
       Time--something about time.
       There, I had it. Ragnarök hadn't yet arrived, so what was I worried about? Thor couldn't die today--not if the prophecies were true. He had to be around for the End Times.
       Didn't he? Or was Odin right in his endless search for ways to avert his fate? Could the foretold future be changed?
       I felt the hair rise on the nape of my neck as Thor dismounted from his goat cart, brandishing the hammer I'd been so proud of creating. He strutted toward the head giant.
       The giant's eyes narrowed. "You're waving that thing around like a toy."
       "Very observant."
       If only I hadn't done such a good job of recreating Mjölnir.
       "Thor, you must not fight them." I stepped closer. "There's something you need to know--"
       "Dare you tell me what to do?" Lightning flashed in Thor's eyes. Distracted for the moment, he let his arms hang at his sides.
       And I saw my chance to fix things.
       I lunged forward, grabbed the fake hammer, and flung it as hard as I could, striving for height rather than horizontal distance. "Let's move." I spoke curtly, leading the way to the goat cart.
       To Thor's credit, he followed, though he did offer a protest. "Why did you throw away my hammer?" He frowned. "And how did you do it?"
       "I played an April Fool's prank on you. That's not Mjölnir. It's a paper-mâché version."
       Thor pouted. "You mean I didn't wake up as strong as I was in the glory days?"
       "No."
       We leaped into the cart. Thor clucked to the goats, who turned neatly, then sprang off toward home.
       I turned so I could see the goings-on behind us. The hammer had not, as yet, fallen to earth. The giants had not, as yet, realized that standing under a falling hammer, gazing upward, was not the most prudent of actions. We just might escape unscathed.
       I grimaced. The hammer did, indeed, land on one of the giant's heads. Fortunately, they did not immediately pursue us. Instead, they took turns bashing one another with the fake Mjölnir, laughing when it didn't really hurt.
       "They may make the wrong inference," I said.
       "In that case, I'll be ready for them with the real thing." Thor grinned.
       I'd forgotten how uncomfortable a goat cart ride can be. By the time we arrived in Thor's yard, I felt as though every bone in my body had been removed, shaken, and replaced, with a few mix-ups in the process.
       Anticipating Thor's wrath at my could-have-been-fatal prank, I disembarked quickly.
       But his expression, when he turned to face me, looked dreamy. "Just for a moment, when I hefted the hammer, I thought--" He shook his head. "I miss the old days."
       I thought of that moment of doubt I'd had when I wondered whether the prophecies really could be changed. Perhaps my relationship with Thor did not have to be what it had deteriorated into after that nasty business with Baldur. Maybe, in pulling my April Fool's Day prank, I'd subconsciously been seeking to return to the time before everything went sour. Deep in thought, I turned to leave.
       "Loki," Thor said.
       I turned to face him.
       "Don't let it be another century before you visit again, okay?" He grinned.
       "I won't," I said. And meant it.