'Grimm' season 5 spoilers: Nick, Hank face the Rat King in episode 5

The Rat King will give the team chills in the upcoming episode of "Grimm."Facebook/NBC

The mythical Rat King is on the loose and it is killing Wesens in the upcoming episode of the hit NBC series "Grimm."

In "The Rat King," SpoilerTV reports that Portland Police Department (PD) will be tapped to investigate a double murder. But when Nick (David Giuntoli) and Hank (Russell Hornsby) learned that the victims are Wesens, the investigation takes a turn for the worse. It appears that the dead men are out hunting at a local dumpsite when they encounter the fabled creature. Two perished while one is missing. Nick must then do his job both as a police officer and a Grimm.

According to folklores, rat kings are basically a number of rodents stuck together at the tails. All together, they form a gigantic creature, which is sure to give anyone a nightmare. Wesens stand no chance against the dreaded monster. As Monroe (Silas Weir Mitchell) says in the promo, a twenty-foot "ratzilla" can be a little hard to imagine. But when they see it rise from the dumps, the horror in their faces is real.

Also in episode 5, Nick also has to deal with his personal life, as he finds a very badly injured Trubel (Jacqueline Toboni) on his doorstep. How will this affect his budding relationship with Adalind (Claire Coffee)? At the same time, Nick finally gets the chance to meet the infamous Meisner (Damien Puckler). What will come out of this encounter?

Meanwhile, speculations are ripe that Juliette, played by Bitsie Tulloch, will return in the series. These come after the actress is seen joining the celebration of the series' 100th episode. Season 5 premiered with Juliette's funeral. Since then, she has appeared in a number of flashbacks. It remains to be seen, however, whether she would make a special appearance for the landmark episode.

When asked about her insights regarding the "Grimm's" long run, Blastr reports that Tulloch thanked the fans for the 89 great episodes so far. She also shared that her portrayal of Juliette had been fun.

"I'm very grateful to our fans because we wouldn't have made it this far without them. The sci-fi fans are just the best to have. Very loyal and very smart," she said.

"Grimm" season 5 airs Fridays at 9 p.m. EST on NBC.