"The Key" is the third episode of W.I.T.C.H.
When Caleb discovers that Blunk took the key he was supposed to leave behind in Meridian for Vathek, the girls return to Meridian to return the key before Cedric and Phobos discover Vathek is a spy for the rebel army.
They plant the key on a general, Raythor and he, instead of Vathek will be thrown into the Abyss of Shadows. In the B-story, Hay Lin decides to create for Caleb some new clothes to help him blend in on Earth.
- This episode marks Raythor's first speaking role.
- This is the only episode in which the girls make certain noises while transforming. For example, Taranee makes a startled noise while Hay Lin and Irma giggle before saying their elements Cornelia just says her element.
- From this episode onwards, Will makes an indistinct and inaudible sound during the transformation sequence. Despite various theories and different interpretations in closed captioning, her call-out remains shrouded in mystery. Candy Milo, who voices Irma Lair, revealed that Kelly Stables, who voices Will Vandom, never made a call-out word for that scene and it was an audio glitch. This was fixed in season two when Will says, "The Heart" and later "Quintessence".
- When the girls are talking to Blunk, Irma's skirt is green in one of the scenes.
- When Will pulls the eel off of Taranee's head, Irma's voice is heard.
- The key in this episode is a different key than the key seen in "It Resumes".
- Irma was imitating Elvis Presley when she said, "Thank you. Thank you very much." This was Elvis Presley's main tagline in the 1950s and the 1960s.
- When Will hugs Hay Lin, her arms pass through Hay Lin's wings.