“Many years ago, men and lions used to live in peace together and were allies. They protected each other. But little by little men forgot about their deal and in the end the lions did the same.” These are the words that Lionel’s dying grand-father whispered to him in his village in Africa. Lionel is an 11-year-old boy who leaves happily in Switzerland with his mother and step-father. During a school trip to the zoo, Lionel is irresistibly attracted to an old lion lying in a cage. The lion starts to communicate with him and asks him to find a way to set him free in order to go back to Africa. With the help of his best friend Federico and of his classmates, Lionel is determined to keep his promise…