When Henri writes a text in class about his life, he says that his mother was a spy who entrusted to a man by giving him a pendant with a lock and she would keep the key. The day she finds him, she could recognize him by using his key. Henri is a little mythomaniac, his imagination is overflowing, despite that he often goes unnoticed at school. During the year, with his friends LÔeo and F.-X., they will try to get closer to girls. A complicated mission when one is twelve years old and that is accompanied by a shyness that the hero did not suspect in itself with regard to the young girls that he is not sure to understand since he perceives them like extraterrestrials.