The holidays have just begun and the parents of Carlinhos and Casca decide to take them to the Butantan Institute. There, they meet Isadora and Chica. Walking through the immense institute they end up finding ghosts, until they discover that one of the ghosts is the grandfather of Carlinhos and Casca, Reginaldo. The scientist then gives a great mission to the children: to recover the Serum of Immunity. But the children are faced with numerous challenges along the way, among them Barbara, the institute employee who tries with all the odds to discover their secret and gain the position of director and also the Pharaoh Sobekhotep I, who seeks the serum. In the search for the object and with the help of the ghosts, the children live a great adventure.