NBC has released the synopsis for episode #505 of Grimm, which you can check out below. The installment, titled “Rat King,” is officially described as follows:
THE WHOLE IS DEADLIER THAN THE SUM OF ITS PARTS – CARLSON YOUNG, JACQUELINE TOBONI AND DAMIEN PUCKLER GUEST STAR – Nick (David Giuntoli) and Hank (Russell Hornsby) are called to the scene when three Wesen go out on a hunt at a local dump and get more than they bargained for when two turn up dead after they encounter the mythical Rat King. Meanwhile, a very badly wounded Trubel (guest star Jacqueline Toboni) is taken to the hospital and Nick finally meets Meisner (guest star Damien Puckler). Silas Weir Mitchell, Sasha Roiz, Reggie Lee, Bree Turner and Claire Coffee also star.
Grimm “Rat King” airs Friday, December 4, at 9pm on NBC.