Willie es un joven hipopótamo travieso que se escapa de su corral en el parque safari y hace muchas travesuras. Todos las ganancias se destinan a Save the Children. Esta edición especial incluye una historia nueva (La Entrega Navideña de Willie) y cuatro historias publicadas anteriormente (Nadar, Cumpleaños, Boda y Cachorros de León).
This is the Spanish version. Willie is a naughty young hippo. He lives in a safari park and when all the visitors leave for the night he escapes from his pen and gets up to mischief. He is helped by his friends. They are Benji the rabbit, Fanfan the elephant and Jiffy and Joffy, the young giraffes. This is the hardback delux version of all five Willie stories. Unlike the stories that have been published separately as paperbacks, this one does not contain pages to colour in. All profits to Children in Need.