'Grimm' Exclusive Season Finale Sneak Peek: Nick and Rosalee Team Up to Stop the Undead [Video]

Yahoo! TV

NBC's dark and magical police drama "Grimm" is nearing its Season 2 finale, "Goodnight, Sweet Grimm," and we've got an exclusive sneak peek to sink your teeth into -- even if the recent rash of zombies aren't flesh eaters.

The undead are popping up in Portland, and not the slow, lumbering kind. These zombies are filled with rage, move quickly, and are wreaking havoc. "I know he looks dead, and he probably was for a little while, but he's not now," says Det. Nick Burkhardt (David Giuntoli), while he and the gang are handcuffing a body.

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The group is trying to figure out what they're up against and are hoping that Rosalee (Bree Turner) will have some insight. After getting a few details from Nick, she appears to have an idea.

"There's a pretty big pharmacology associated with this," she says, grabbing a book. "There are several categories of trance-like states." She finds the page they're looking for. Apparently, this "infection" is caused by several types of Wesen, including Cracher-Mortel. "Good lord! Is there any treatment?" asks Monroe (Silas Weir Mitchell). "There seems to be," says Rosalee, but it's not going to be easy.

The "Grimm" Season 2 finale airs Tuesday, 5/21 at 10 PM on NBC.