Scott (Tyler Posey) and his pack - once he reassembles it - will be battling The Beast when MTV's Teen Wolf returns to finish off Season 5 on Jan. 5.

According to the new trailer, the Beast is so terrifying that it will force Scott to have to work with Theo (Cody Christian) if he wants to keep everyone alive. That's a pretty tall order considering Theo tried to kill Scott and then raised his own pack of chimeras (genetically engineered supernatural hybrids) from the dead.

Even with all that, they'll also need some outside reinforcements. Chris Argent (JR Bourne) has returned from his grief trip abroad and he's brought his father Gerard (Michael Logan) to help with the hunt.

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The last time Teen Wolf fans saw Gerard, he was trying to force Scott into making him a werewolf so he could survive his cancer diagnosis.

Whatever the Beast is after, Lydia (Holland Roden) will be a key in stopping it, as Stiles (Dylan O'Brien) seems determined to save her from Eichen House in the final scenes of the clip. Check it out below:

Teen Wolf returns Tuesday, Jan. 5 at 9/8c on MTV.