On Friday, NBC will air the second to last episode in Season 3 of "Grimm," which includes more background info about Trubel and a mysterious duo that will come to Portland to find of Nick.

In the upcoming episode, which is called "The Inheritance," Nick and Hank will dig deeper into a double homicide that's linked to the Verrat. Meanwhile, Theresa "Trubel" Rubel will end up meeting a father-and-son team that traveled a long way to find "the Portland Grimm," reports The Hollywood Hills.

Since arriving in Portland, Trubel has developed a reputation for being the tough new Grimm in town who almost killed Monroe. In the penultimate episode, viewers will learn more about her troubled past. NBC released a teaser clip from "The Inheritance" that shows Trubel opening up about the first time she discovered that she was a Grimm while having dinner with Nick and Juliette in their home. In the video, Trubel says she was first called a Grimm when she was an 11-year-old girl after she brutally attacked a man that tried to rape her.

Series co-creator James Kouf told TVLine that fans can expect to see Trubel kick butt "very spectacularly," and that she won't tie into any existing storyline. Instead, "she's got her own deal," he said.

In the meantime, Adalind's perception of motherhood has drastically changed now that little Diana has been taken from her. The Hexenbiest feels "a kind of love that she has never felt before, because she's always been about herself," co-creator David Greenwalt said. "Now, suddenly, there's another very large number in the equation. Certainly she has great motivation for everything she's doing."

Greenwalt also hinted at what's to come in the May 16 season finale. "We have doozies of cliffhangers that should be even more exciting than previous years," said Greenwalt. Because Monroe and Rosalee's wedding will attract a guest list full of Wesen, Nick will try to disguise the fact that he is a Grimm by wearing sunglasses, which may or may not work. Someone is also "gonna get hurt" in the episode, Greenwalt added.

According to Dread Central, the synopsis for Episode 3.21 states:

"Nick (David Giuntoli) and Hank (Russell Hornsby) are called to investigate a double homicide and quickly learn the victims were from a special section of the Verrat tasked with finding rare objects pertaining to the Wesen world.

"Trubel (guest star Jacqueline Toboni) gets involved with a mysterious father-and-son tandem that crossed the country in a desperate attempt to deliver invaluable cargo to "the Portland Grimm."

"Meanwhile, Captain Renard (Sasha Roiz) begins to grow suspicious of Adalind's (Claire Coffee) recent behavior and quietly decides to put extra eyes on her. Bitsie Tulloch, Silas Weir Mitchell, Reggie Lee, and Bree Turner also star. C. Thomas Howell, Sam Anderson, and Lucas Near-Verbrugghe guest star."

"Grimm" Episode 3.21 "The Inheritance" airs on NBC on Thursday, May 8, 2014 at 9 p.m. EDT.

Watch a preview below.