Free Curse of the Ancients by Matt de la Pena

man.
    “Dak!” Sera shouted.
    “Dak!” Kisa shouted.
    Dak and the man both tumbled into the jungle brush, and the back of Dak’s already wounded head smacked into a tree.
    He was dazed.
    The whole jungle swirled around him.
    He could hear details of sound he’d never heard before: the whining of mosquitoes and the hot wind rustling the leaves of every tree in the jungle and the songs of faraway birds and the cracking of twigs as he scrambled back to his feet without even telling himself to scramble back to his feet. He found himself face-to-face with the man he’d just knocked over.
    The man was grinning. “Glad you could join us,” he said.
    Over the man’s shoulders Dak saw Sera and Kisa trying to wrestle the other guy to the ground. The Infinity Ring lay in the grass near their feet.
    He lunged for the man again, but the Maya stepped to the side and threw Dak to the ground. He looked up at the man, who was still grinning, knowing Dak was no match, especially in his current physical condition. And Dak saw that the other dude now had Sera and Kisa pinned to the ground, a firm grip on each of their necks.
    It was over.
    The man in front of Dak stepped on Dak’s back and told his friend, “Release the younger girl,” he said.
    The man did, and Sera stood up, looking very hesitant. “Dak,” she said. “You’re okay.”
    “Well, technically not at the moment,” he said, pointing up at the man standing on him. “But, yeah, I’m no longer bedridden. What’s going on here?”
    “I’ll tell you what’s going on,” the man above him said. “We came here to retrieve a local codex, but we’ve stumbled into something potentially even greater. This metal thing your friend has.”
    “Our king, Yuknoom the Great, will be very happy,” the other man said.
    “He’ll be even more satisfied when we understand how to use it.” The man standing on Dak reached down for his obsidian knife. He dug a knee into Dak’s back and held the knife to his neck. “So we’re clear about things,” he said to Sera, “you’re going to explain how the item works, or I’m going to slice your little friend into several pieces.”
    “Easy with all that ‘little’ talk,” Dak said. “Besides, the item in question no longer even works. Tell him how I broke it, Sera.”
    Sera shot him an uneasy look.
    “Wait, you fixed it?” Dak said.
    “Sort of.”
    “How could you?!”
    “Quiet!” the man kneeling on Dak said. “If you continue talking, I’ll slice you up just to get some peace and quiet. Now, go on.” He motioned for Sera to pick up the Ring.
    Sera slowly reached down, pulled the Ring off the grass.
    “First of all,” the man continued, “what is it?”
    Lie to him
, Dak thought.
Make something up. Tell him it’s a can opener.
    “It’s a time-traveling device,” Sera said.
    Dak let his face fall into the grass.
    “It allows you to warp to whatever era you program into it,” Sera went on. “We are from the future.”
    The man holding down Dak looked at his friend and said, “Are you hearing this? We will be legends in Calakmul!”
    “Yuknoom will build temples in our honor,” the man replied.
    Dak lifted his head. Sera was holding the Ring out for the men to see. Kisa was squeezing her eyes shut, like she was injured.
    “How do you go to another time?” the man above Dak asked.
    “It’s simple,” Sera said. “You just program in —”
    “Uh, Sera?” Dak interrupted. “Maybe a little less detail here?”
    “As I was saying,” Sera said, keeping her eyes on the man, “you just program in your desired year and geographic location, and the machine will take you there. But there’s a catch.”
    “And what is that?”
    “The machine will not work unless the three of us” — she gestured to herself, Dak, and Kisa — “are in physical contact with it. It is programmed to respond only to our DNA.”
    The squat man looked at his friend. “What is DNA?”
    Kisa began humming in a strange way,