Ethan sat up, blinking against the brightness, his heart pounding with both excitement and confusion. "Where am I now?" he wondered aloud, brushing sand from his clothes. He had been through this routine countless times, each morning awakening in a new era, each day a new puzzle to solve in his quest to return home.

Cleopatra, queen of Egypt, stood nearby, her eyes sharp and discerning. She noticed the boy's curious attire and approached with a smile. "You seem out of place, young one," she observed. Ethan nodded, captivated by her elegance. "I am," he admitted, "I'm trying to find my way back home."

Cleopatra listened intently as Ethan explained his plight. "Time is a river," she mused, "and sometimes, it can be crossed with the right vessel." Her words sparked an idea in Ethan's mind. "A vessel," he repeated, feeling hope stir within him.

Ethan and Cleopatra's journey led them to an old scholar, a man with knowledge that spanned centuries. His study was filled with scrolls and artifacts, each telling stories of the past. "Do you believe in the power of time?" Ethan asked him eagerly.

Leonardo da Vinci, who had crafted the device, had inscribed it with secrets of the universe. Ethan held it carefully, feeling its potential. "This could be your vessel," Cleopatra encouraged, "a guide through the currents of time."

Ethan took a deep breath, his heart steady with newfound resolve. "Thank you," he said to Cleopatra, gratitude shining in his eyes. "May the river carry you safely home," she replied. With a final look at the ancient world around him, Ethan activated the astrolabe, feeling its power surge through him as the stars above seemed to spiral into a new constellation.