'Supernatural' first look: Felicia Day returns as Charlie as the Winchesters meet Dorothy of Oz

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The Winchesters are about to follow the yellow brick road in an upcoming episode of "Supernatural" ... with returning fan-favorite guest star Felicia Day.

Sam and Dean's tech-saavy friend Charlie will be making her way back to the Men of Letters bunker in episode 4, "Slumber Party," just in time to help the Winchesters battle the Wicked Witch of Oz after they accidentally set her and Dorothy free from an enchanted wall in the bunker. The resulting magical fight is so massive, the Men of Letters bunker that Sam and Dean have worked so hard to make their home might not survive.

The CW just released first look photos from the episode airing Tuesday, Oct. 29, and the hour will allow viewers to see more of the Men of Letters bunker, including the garage that houses some pretty cool vehicles.

Read the full synopsis of the episode below:

"Sam and Dean discover that the table in the Men of Letters house (the one that lit up like a Christmas Tree when the angels fell), has an ancient computer attached to it.  They figure if they can get the computer on, they can track the angels.  Who better to call for help than the best IT girl there is, Charlie (guest star Felicia Day)?  While moving the massive computer, they dislodge a hidden hexbag that unleashes a magical green-webbed wall.  Sam and Dean break through it and discover the one and only Dorothy (guest star Tiio Horn) from Oz.  She had trapped herself and the wicked witch (guest star Maya Massar) in the web years ago to stop the witch from finding the key that would open the gate that connected their world with Oz.  With the wall broken, a massive and magical fight ensues that threatens to destroy the Men of Letters house."

Check out the "Supernatural" Season 9 first look photos here

"Supernatural" airs Tuesdays at 9 p.m. ET on The CW.

Photo/Video credit: The CW