It was an ordinary morning. Morgan, a thirteen-year-old boy, and his friend Eva were sitting in their favourite café talking about the latest astronomical discoveries. Morgan was a big fan of science, and astrophysics was his favourite field. Suddenly, he noticed an old man approaching them with a shiny gold watch on his wrist. The old man, seeing Morgan's interest, approached and said: 'This watch is special, it has the power to transport you to any place in space-time. I would like to give you this power, but remember one thing - this power carries great responsibility'. Morgan, shocked, accepted the watch. At first he thought it was just a prank, but when he pressed the button on the watch and found himself in the middle of the Battle of Grunwald, he realised it was no prank. The watch was real. Everything changed when one day Eva didn't turn up for an appointment. He called her, sent messages, but received no reply. His concern grew when he found her backpack abandoned in the park and in it a note, 'Help me...'. Desperate, Morgan looked at his watch, wondering if he could use it to find Eva. But when? Where? What was the limit of responsibility the old man had spoken of? Did he have the right to interfere with the past or the future? After all, a friend was in danger. Did he have a choice?