One story ends; another begins...
Mason Gideon thinks he’s just a normal kid living in modern-day Wales, but on his thirteenth birthday, everything changes when he discovers he can use magic.

After accidentally using that magic to defend his friend from the school bully, he attracts a lot of interest that puts him and those he cares about in danger.

Out of the shadows comes a secret organization, founded by the descendants of the Knights of the Round Table, informing him of a prophecy about the sword Excalibur and King Arthur’s lost son. His magic also draws the attention of the ominous Arthurian figure of Augustus Blackthorne, an immortal who seeks to use Mason to recover Excalibur for himself.

As Mason and his friends race across Great Britain deciphering clues to find the sword, they encounter both heroes and enemies straight out of Arthurian legend. But when the time comes for Mason to retrieve Excalibur, can he overcome his doubt about whether he truly deserves to wield the sword?