Nick (David Giuntoli) and baby Kelly in Grimm 5x15 ('Skin Deep')
Nick (David Giuntoli) was having an adorable moment with baby Kelly when Eve (Bitsie Tulloch) called, so he let Adalind (Claire Coffee) answer his phone. NBC/Grimm's Official Facebook Page

“Grimm” Season 5, Episode 19 is called “The Taming Of The Wu,” but it could also be all about the saying that the third time -- or in this case, the third Hexenbiest -- is a charm. The NBC promo video for the next episode seems to promise a grand unveiling.

Spoiler alert: This update contains “Grimm” Season 5 spoilers. Details include the highlights of the Episode 20 synopsis.

Adalind (Claire Coffee) and Diana (Hannah R. Loyd) are finally reunited. Renard (Sasha Roiz) gets the privilege of seeing their daughter first, because Black Claw used Diana as a bait to convince him to embrace the organisation’s endeavours. What does this mean for Nick (David Giuntoli), who knows Adalind is not being very truthful to him?

More from Episode 18: Juliette or Eve (Bitsie Tulloch) sees Asset X3, Diana Schade Renard, as M.I.A. and she gets visibly worried. For a moment, she drops the mask of Eve and becomes Juliette again. It seems Hadrian's Wall had Diana, but their security has been compromised and now Black Claw has custody of the powerful young girl.

In the same “Grimm” Season 5 episode, Sgt Wu (Reggie Lee) shows the viewers his wolf transformation. Neither Grimm Nick nor his cop partner Hank (Russell Hornsby) is aware of his situation. Wu, bitten by a Lycanthrope in Episode 14 (“Lycanthropia”), is now showing signs of Wesen-ness, or more accurately, werewolf-ness.

Incidentally, Hank has reunited with his therapist Zuri Ellis (Sharon Leal) and it seems the potential for a real romance is great between this Wesen and regular man cop. (Wu is behaving like a Wesen, while Nick’s other cop friend is dating one. Before that, Nick’s ex has turned into a Hexenbiest. It is hard to imagine that anyone in the series would remain a regular person by the end of the series.)

“The Taming of the Wu” could be a Wu-centric episode, but the viewers could also find out more for about Diana, Adalind and Renard. What will this family do next? Will Eve fight against them all, or will Diana and Adalind join Team Nick with Eve? How would Diana react to Adalind and Nick’s son, baby Kelly?

WATCH: ‘Grimm’ Season 5, Episode 19 Promo Video (NBC on YouTube)

Sean Renard’s mother Elizabeth (Louise Lombard) is a Hexenbiest, which means there are actually four notable ‘biests in the series, in order of appearance: Adalind, Diana, Elizabeth and Juliette. However, Renard’s mom has appeared in only a few episodes so the NBC promo is counting in Diana as the third Hexenbiest.

“Grimm” Season 5, Episode 19 airs next Friday, April 29, on NBC.