The night was cool and quiet, with only the wind humming somewhere outside the library windows. Michael and Lena, history students at the university, were preparing for an exam. They sat at a long oak table covered with stacks of books. Lena held up a bound volume bearing golden letters. "Look, I don't think I've ever seen this one," she said, running her hand over the cover. "Open it!" - Michael hazarded. Lena raised her eyebrows slightly, then turned the page. At the same moment, the light went out. Silence fell for a moment, until suddenly a blinding beam of light shot out of the book, surrounding them both. When they came back to consciousness, they felt something soft underfoot. Overhead, birds sang and tall grasses rippled around them. Gone were the bookcases, the books and the familiar room. "What the...?" - Michael tried to understand what had happened. They looked around. Just nearby, on the sand, lay the same book. Lena carefully picked it up. On the first page was the date: "1472". Silent voices and the clatter of horses' hooves came from far away. With difficulty, they hid behind a large boulder. For a moment, they watched a group of people in medieval costumes pass through the meadow. Michael lowered his voice. "It can't be... It looks like... we've travelled back in time?" Suddenly Lena felt that something was watching her. From far away, from behind the trees, two yellow dots flashed. As she looked more closely, the animals became quiet and the air thickened with anxiety. Someone or something had moved towards them amidst the rustling grass....