When thirteen-year-old Arthur of Gal, the future King Arthur, accidentally time-travels to the twenty-first century, Sophie Sawyer, twelve, must convince him to return and correct the time line.

Sent by a banished Merlin to protect King Arthur, a sixteen-year-old impersonating the deceased Guinevere struggles to fit in at Camelot where the magic she practices is banished.

After a mysterious plague threatens Camelot, Calib and Cecily set off on a voyage to Avalon to find a cure and need to use magic and the help of friends to solve the mystery of the plague and return in time to save Camelot.

At the flea market nine-and-a-half-year-old Chase and his younger sister Ava acquire an old suitcase filled with rows of carefully packed strange objects, and when they handle one of the objects (a dragon-headed doorknob) they find themselves in King Arthur's castle, on a mission to save the King--and pursued by a strange man whom they first saw at the flea market, who is after their suitcase.