NBC's "Grimm" ended the hour with quite the twists: Diana revealed following a nightmare that the Skull guy is not only after her but her brother too, and the cliffhanger saw the death of two series leads. When the NBC show aired, it introduced David Giuntoli's character Nick, a homicide detective that discovers his aunt has kept a family secret. He's a Grimm, a hunter of supernatural beings called Wesen that appear human but can woge to an animal-like state. Each episode ties to mythology, and Grimm fairytales. Six seasons have seen a lot of tragedy for Nick as the series began with the death of his aunt, his girlfriend Juliette became a hexenbiest and tried to kill him, and his mother's head was sent to him in a box.

As the show winds down, many wonder whether or not the show will receive a happy ending.

What's happened so far on 'Grimm'?

Despite the shortened season, "Grimm" reached it's 100th episode, delivered its craziest episode, and had a big surprise for Monroe (Silas Weir Mitchell) and Rosalee (Bree Turner) who discovered they're expecting not one but three babies. The season also brought the series full circle, bringing an end to the mystery of the keys, which led Monroe and Nick to the Black Forest where they discovered a well-hidden magic healing stick. Even stranger, the stick opened up a door within a mirror that led to another world. For episodes, the show has teased a Skull guy that has been trying to pull Eve (Bitsie Tulloch) through the mirror, so Friday's hour not only fully introduced him but brought him into Portland to cause chaos.

That's not the only development.

Longtime frenemy, Captain Renard (Sasha Roiz) began the season planning to take over the city as mayor and get rid of Nick, but a turn of events that puts his and Adalind's daughter in the center has him finally on the Grimm team's side. That's not the biggest surprise of the hour, as the show delivered a big moment between Nick and Adalind (Claire Coffee) that involved an exchange of "I love you," and the deaths of fan favorites Wu and Hank.

What to expect from the series finale

When questioned about whether or not the deaths of Wu (Reggie Lee) and Hank (Russell Hornsby) are permanent, David Giuntoli commented that he didn't think he could talk about that. Following their deaths, Nick will be in a state of grief in the finale, acting on vengeance with nothing strategic thought out.

The tragic turn of events goes back to the theme "Grimm" had in place since the beginning when Nick's aunt warned him about having relationships because everyone he loved would be in harm's way. Throughout the series, this has proven to be true as everyone that has come to his aid has suffered the consequences. However, the actor teases that the show will make fans happy, and will wrap up the storyline, leaving no questions. Giuntoli added that the final hour will play with space-time which he compared to being on a ray of light, and will contain time jumps. Yes, fans will see the future on "Grimm."

Nearing the end of "Grimm," David Giuntoli has been cast in the CBS pilot "Mission Control," alongside Poppy Montgomery ("Unforgettable"), which will follow the story of the next generation of NASA astronauts and scientists as they balance their personal lives with a critical mission.

The "Grimm" finale airs on NBC March 31.