Time and Space Investigation Department 7: The Little Mercenary on the Hundred Years Battlefield

In 1415, a major battle between the British and French armies took place in Agincourt - the Battle of Agincourt. The Alpha team's crossing operation deliberately avoided the date and location of the war, but they didn't expect to encounter the war. Kevin was even separated from Sean and Zhang Lin! Kevin was mistaken for a British mercenary, and Sean and Zhang Lin were regarded as French mercenaries. What's going on?