In The Gateway to Byzantium, Halvdan, Meia, Björn and Grimulf finally reach Byzantium where Halvdan hopes to find his father. They search in Sofia’s church where they find Halvdan’s name etched on a railing. They receive unexpected help from a girl called Disa who leads them to the City Prison where from a terrace rooftop they catch sight of Halvdan’s father. But how can they free him? And if that’s not enough they have to somehow get into the emperor’s palace and take the red ruby, Oden’s other eye.

Halvdan the Viking is a series by Martin Widmark and illustrator Mats Vänehem, about the young boy Halvdan who finds himself in one adventure after the other, together with his friend Meia.