“GRIMM”: Trubel, left, runs into a father-and-son team who have traveled a great distance to track down “the Portland Grimm.” (Scott Green/NBC)

“Dateline NBC” (NBC at 8 p.m.) investigates the case of a popular young woman who goes missing on her son’s fifth birthday, which leads the local police department to multiple suspects and gruesome possibilities.

“Key & Peele’s” Keegan-Michael Key is the guest comic on “Whose Line Is It Anyway?” (CW at 8).

Carrie stumbles into a case when she attends her high school reunion and one of her classmates is found dead on “Unforgettable” (CBS at 8).

While Nick and Hank investigate a double homicide linked to Verrat on “Grimm” (NBC at 9), Truble runs into a father-son duo who have traveled long and far to find “the Portland Grimm.”

FINALE WATCH: During “Hawaii Five-0’s” (CBS at 9) fourth-season finale, Grover is forced to steal $100 million to get his kidnapped daughter back, and Wo Fat escapes prison. Nick Jonas is back as a guest star.

“Shark Tank” (ABC at 9) hears pitches for a light and healthy wine, an alternative to cinnamon rolls, a collapsible kayak, and offers an update on a Barbara Corcoran-backed food truck from Season 4.

FINALE WATCH: A full-blown brawl breaks out at the mansion where Gloria pulls a knife and Sofia breaks her foot on the Season 2 finale of “Marriage Boot Camp” (WE tv at 9).

On the special “The Silk Road Ensemble With Yo-Yo Ma: Live From Tanglewood” (WETA at 9:30), the ensemble, which was formed by Yo-Yo Ma, celebrates its 15th anniversary at Tanglewood in Massachusetts.

FINALE WATCH: Danny sneaks into an off-limits case and is put on modified duty, but not before he alerts Frank, who digs more into the file only to discover a huge scandal on the Season 4 finale of “Blue Bloods” (CBS at 10).

With a penchant for breaking the rules, Hannibal leaks information about Abigail to Will on “Hannibal” (NBC at 10), while Alana begins to worry about Will’s sanity.

Actor James McAvoy and comedian Amy Schumer are on “The Tonight Show Starring Jimmy Fallon” (NBC at 11:35), with music from Tune Yards.

“Castle” actor Nathan Fillion comes to the “Late Show With David Letterman” (CBS at 11:35), along with stand-up comedian Tom Dreesen and musical guest Hunter Hayes.

“American Idol’s” Jennifer Lopez and actress Elisabeth Moss stop by “Jimmy Kimmel Live” (ABC at 11:35), with a performance from Sleepy Man Banjo Boys.

Rachel Lubitz