Twelve-year-old Bobby hates middle school but is fascinated with King Arthur. In an effort to rebel against his father's oppressive expectations, he lets his grades drop-until his dad promises to take him to Camelot Theme Park if he gets all As.

When the long-awaited day finally arrives, Bobby is magically transported directly back to ninth-century Britain through a secret door in the park's basement museum. Suddenly grateful for all his recent schoolwork, Bobby must use everything he's learned, from history to science, if he hopes to help the people he meets-and survive himself. Before...