Little Einsteins (2005)

S1E14 The Good Knight and the Bad Knight

The kids learn that a noble knight is imprisoned in a castle by an evil knight, prompting them to come up with a plan to save him. However, they first need to locate a magical key to unlock the castle doors. Unfortunately, the fortress is filled with various traps, so the children must rely on their cleverness and teamwork to outsmart the wicked knight and ensure their rescue mission succeeds.