It's 490 AD. Uther Pendragon, the tyrannical King of the Britons, rules uncontested. Eleven years ago, the heroic King Meliodas led a rebellion against him.
With Meliodas a martyr, and his isle of Lyonesse cast into the sea by a coven of Uther's wicked sorceresses, Queen Isobelle fled into hiding with her infant child Triston.
After befriending a mysterious blue dragon he names Chomper, Triston embarks on a mission to do what he believes is right. This hero's journey, however, leads him on a path from which he may never be able to return.