Little Einsteins

The Good Knight and the Bad Knight (1x14)

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When the children discover that a good knight has been trapped inside of a castle by a bad knight, they decide to rescue him, though they need to find an enchanted key before they’ll be able to do that. Unfortunately, the castle is guarded by all types of traps and the children will need to use their wits if they wish to foil the bad knight’s plan.