NBC may suffer a dearth of monsters when Grimm returns for season 6.

The Friday night spooker snagged a renewal earlier this month, but Nick (David Giuntoli) and the Scooby Gang might not enjoy a full compliment of episodes. After airing 22 hours for the last five years, there is a chance Grimm could find it's season cut in half.

As of Friday, the veteran series was only scheduled for 13 episodes. Although shorter seasons often indicate a looming cancelation, fans should worry just yet.

"That is not a fixed number, as I hear the pickup is for a minimum of 13 episodes, with a likelihood for more," Deadline's Nellie Andreeva reported. "The move was made to give NBC brass scheduling flexibility."

Grimm is often plagued by cancelation rumors, but, so far, the 9 p.m. drama has continued to keep its head above water. This season has already brought about several major reveals - the treasure of the Seven Knights was unearthed, Hadrian's Wall and Black Claw come out of the woodwork, and Juliette (Bitsie Tulloch) found new life as Eve - and the finale will be packed to the brim with revelations.

"We didn't know 100 percent if we were going to get a sixth season," Giuntoli explained in a Facebook live stream. "We do have one, thank goodness...but we were writing to a 'maybe' ending, so [there's] a lot of big, big stuff happening [in 'The Beginning of the End']."

Tonight, the Portland crew will deal with Wu's dangerous transformation. The story will lead into next week's "Taming of the Wu".

"Suffering from the bite he sustained, Sgt. Wu (Reggie Lee) becomes entangled in a surprising altercation that may land him in hot water," NBC teased. "After meeting the mysterious Bonaparte (guest star Shaun Toub), Adalind (Claire Coffee) is faced with a difficult decision that could change her and Nick's (David Giuntoli) lives forever. Meanwhile, Hank (Russell Hornsby) gets even closer to Zuri (guest star Sharon Leal) and their relationship begins to take shape."

Catch Grimm Fridays at 9 p.m. ET on NBC.

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