What if one man could change history? History professor Johnathan Lambert is on a business trip in the French countryside when his train enters a small tunnel containing a strange phenomenon – emerging from the other side without him and leaving him stranded in 17th century France. Agent Nadeau, a veteran of the Central Directorate of the Judicial Police is tasked with the investigation of the missing passenger. But there's only one problem with the investigation. Johnathan Lambert doesn't exist, and Nadeau is faced with a difficult question. How do you find someone who doesn't exist? Lambert wakes up to find himself displaced in time – somehow transported back to the reign of the last French King and Queen, Louis XVI and Marie Antoinette. How can a modern man survive in the past with only the clothes on his back and his wits, on the eve of the violence and turmoil of the French Revolution? Can Lambert prevent the revolution? If he does - how is Agent Nadeau's modern world affected by the changes to the past? Follow the stories of these two men, one struggling to survive in the turbulent past, the other trying to track him down in the modern era, looking at clues to solve the disappearance of the missing passenger on the train.