Grimm Season 4 finale
Nick and Juliette in Grimm season 4Grimm/Facebook

Grimm season 4 returns with a new episode on 24 April, at 9pm on NBC.

Episode 19 is titled Iron Hans, where Adalind will finally tell Nick that she is expecting his baby.

Click here to watch the episode online on the NBC website and click here to watch it via live stream online.

The official synopsis reads as follows:

The hunt is on as a Wesen right of passage becomes deadly. Nick (David Giuntoli) and Hank (Russell Hornsby) are brought in to investigate a homicide they learn is connected to an age-old Wesen rite of passage. Meanwhile, Juliette (Bitsie Tulloch) makes a surprising new ally. Elsewhere, Captain Renard (Sasha Roiz) continues to battle a darkness within, and Nick finds hope for Juliette in the last person he expected - Adalind (Claire Coffee). Silas Weir Mitchell, Reggie Lee, and Bree Turner also star.

Going by the promo, Adalind's revelation of her pregnancy to Nick creates a lot of complications.

The promo ends with Juliette seeing Nick and Adalind together, and saying, "So, it's true. I am going to rip this b***h's throat out."

According to a report in TVguide, the Royals will converge on the city when Adalind's baby Diana hits town. "She's coming back ... in a slightly different form this time," executive producer David Greenwalt said.

"Everybody wants to get their hands on her, and the Royals have brought out all the big guns for this."

Nick will have two other Grimms backing him up, his mother Kelly and Trubel.

Meanwhile, Adalind is still very pregnant with Nick's baby, and the "ruthless" Hexenbiest Juliette is not happy about it. Expect at least two deaths, and the good guys may be more at risk than you think, says the report.

Monroe will be fighting for his life when "one of his friends shoots him at one point," Greenwalt said.

Executive producer Jim Kouf added, "The captain will be shot again. We have to shoot the captain at the end of every season. It's kind of a thing now."