“Grimm” Season 5, Episode 18 (“Good to the Bone”) airs April 22 on NBC. The new episode synopsis hints at something big happening to Sgt. Wu (Reggie Lee). Meanwhile, lead actor David Giuntoli has recently said Season 6 could be the show’s last chapter.

Spoiler alert: This review contains “Grimm” Season 5 spoilers. Details include the developments in the latest episode, titled “Inugami” (air date: April 15).

Wu gets scratched by a Lycanthrope or a Wesen that acts like the mythical werewolf in Episode 14 (“Lycanthropia”). Since then, he has been fighting off anxiety, nausea and headache among other things. In “Inugami,” a brief scene suggests that he may have gone out at night without recalling any moment of it in the morning.

The clues have been building up, as if preparing the audience for a big transformation. In “Grimm” Season 5, Episode 18, Wu becomes a bad Wesen’s random target. Will Wu transform into a werewolf to save himself? It would certainly be interesting to see how the writers would take Wu from his current status in the show.

In another development, Diana, the daughter of Adalind (Claire Coffee) and Renard (Sasha Roiz) finally re-emerges and reunites with her dad in Episode 17. She is brought in by Black Claw’s Rachel (Anne Leighton), who wants Renard to have a good family picture for the mayoral election. Fans are now asking: Are Rachel Wood and Martin Meisner (Damien Puckler) working together?

Martin and Eve a.k.a. the former Juliette (Bitsie Tulloch) have been working together with Trubel (Jacqueline Toboni) to fight Black Claw. If Martin is double-crossing in any way, Eve would know, eventually. It seems, however, that Eve has no idea on who’s running the Black Claw operations. It is also not clear whether Eve knows that Martin was with Diana in the helicopter that she almost boarded in Season 3.

For now, Eve is keeping her focus in three people: Rachel, Renard and Adalind. She tells baby Kelly’s mother that she would not let Adalind hurt Nick. This should push Adalind to tell Nick that she’s a Hexenbiest again.

‘Grimm’ Season 6: David Giuntoli says it could be the final season

“If we get a Season 6, it could very well be our last season, and it will be the first time that the writers would get to write to an ending. If we do, it'll be a very fun ride, with major events,” Giuntoli told Los Angeles Times in March. NBC ordered a sixth season earlier this month.

With several story arcs up in the air, it could be difficult for “Grimm” fans to accept that there is only one final season of the fantasy series. It seems there is more to explore when it comes to Wu, the ancient magic wand, the mystery tunnel under Nick’s new place and the fight against Black Claw and baby Diana’s new friends (or subordinates). There could be some story in how siblings Diana and Kelly would deal with each other.

Will Diana see Mommy Adalind in “Grimm” Season 5, Episode 18?