Ernest Dingle is a daydreaming adventurer who, along with his loyal dog Dudley, uses a mysterious bathtub time machine to travel back in time to Medieval England. With the help of a colourful bunch of people he encounters en route; Ernest sets out on a thrilling adventure to rescue two young princes locked away in the Tower of London by their evil uncle, King Richard. Each step of the way Ernest and friends are stalked by King Richard's five villainous knights, anxious that the secret of the Princes in the Tower is never discovered. Can Ernest and Dudley rescue the princes before it's too late?