In modern-day Britain, young Alex Elliot is a regular schoolboy struggling with bullies, his absence of a father, and feeling generally insignificant. His mundane life is interrupted when he stumbles upon an ancient sword embedded in a construction site. To Alex's astonishment, he pulls the sword from the stone, unaware that it is the legendary Excalibur. With the mythical weapon in hand, strange occurrences begin to unfold around him, and he starts to realize that his find is more significant than he could have imagined.

The appearance of the sword triggers the awakening of the wicked enchantress Morgana, long-sealed beneath the Earth. As she prepares to reclaim Excalibur and bring about an age of darkness, Merlin, now a youthful incarnation of the ancient wizard, appears to guide Alex. Merlin warns that Morgana's rising is imminent during the upcoming solar eclipse and that Alex must rise as the new King Arthur. To thwart the coming doom, Alex must embark on a perilous quest. With the help of his best friend Bedders, classroom nemesis Lance, and tough-as-nails Kaye, Alex sets out to assemble a new round table of knights and prove worthy of his unexpected destiny. The unlikely young heroes must confront their fears and band together, facing creatures and trials akin to the legendary Arthurian myths of old, to stand against Morgana's malevolent forces.