Allie Pennington (Britt Robertson) is transferred to a new school (Avalon High) where she discovers that her new classmates are reincarnations of King Arthur and his court. Now her mission is to solve the school's mystery before Mordred wins again. Allie also meets the high school football quarterback, Will Wagner (Gregg Sulkin).that brings Arthurian legend alive at a contemporary high school| Allie believes that Will is King Arthur and that a mean classmate Marco is Mordred, but it turns out that Marco is another Knight while Mr. Moore, one of her teachers is Mordred. It's revealed that Allie herself is King Arthur when she draws a plastic sword and it turns into Excalibur. Allie and her friends battle Mordred and after Miles (Merlin reincarnated) summons Merlin's staff away from Mordred, Allie defeats him. Mordred tries to have her arrested in the real world, but she turns Excalibur back into a plastic sword and Mordred/Mr. Moore is taken away as the police think he's insane.