Now that his parents are separated, Ludo has two houses: one in the country, the other in the city. The boy doesn't really like going to his father's house, where he has no friends, even though he loves the hustle and bustle of the city and the traffic lights fascinate him. He is even convinced that a little man is hiding in the pole, working night and day to regulate the traffic. Listening only to his big heart, the little boy will go out into the night to try to reward this valiant worker in the shadows.