Tessa is up to no good on Supernatural.

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The Reaper is reinserting herself into the Winchester's lives, and it doesn't look like it's for the better.

Slated to appear in the season's penultimate episode, Tessa (Lindsey McKeon) will be at the heart of a conspiracy to hurt Castiel's (Misha Collins) cause. When Cas calls on Sam (Jared Padalecki) and Dean (Jensen Ackles) to help determine why his small army was attacked during "Stairway to Heaven," the hunters will discover that not only did the assailant come from within Cas' ranks, but also that Tessa is at the heart of the problem.

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Whether or not she can remain on the side of Team Free Will remains to be seen.

"I am going up to Canada to do more Supernatural next week. I am so excited," McKeon told the Examiner before filming started in April. "This is first of all one of my favorite characters to play. And I just read the script over the weekend and I'm even more excited now because it's a fun little juicy twist. I'm really happy about it!"

Tessa has not appeared on the CW drama since season 6, but her frequent passage between heaven and hell has almost certainly seen some interruptions thanks to Metatron (Curtis Armstrong), Abaddon (Alaina Huffman), and Crowley's recent shenanigans.

Find out what Tessa is really up to when Supernatural airs Tuesdays at 9 p.m. ET on The CW. Click the video below to see Tessa at work in "Appointment in Samarra."

Tags: supernatural the cw television