Riggs (Clayne Crawford) wants to avenge the death of his wife Miranda (Floriana Lima) by killing the man he thinks murdered her. But can his partner Murtaugh (Damon Wayans) stop him from doing the unthinkable?

In the preview clip for Season 1 finale of “Lethal Weapon,” Riggs appears to have abducted Gideon (Matt Passmore) to find out if he did kill his wife just like what Palmer (Hilarie Burton) thinks. In the video, Gideon — who was arrested at the end of last night’s episode for trying to kill Tito Flores’ (Danny Mora) mistress Maria (Daniella Alonso) — is seen chained up in Riggs’ trailer as the Navy SEAL veteran tries to confirm whether Miranda’s death was not accident.

While it’s unclear whether Gideon was indeed behind Miranda’s death, Riggs seems very determined to take Tito Flores’ henchman out. In the latter part of promo clip, Riggs appears to have tied down Gideon’s legs and bound the cartel hitman to a toilet seat with duct tape. But before Riggs can realize his plan, Murtaugh tries to talk him out of it by telling him to let go of the past.

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“You gotta figure out. Do you wanna live? Because if you do, you gotta let her [Miranda] go,” Murtaugh tells his partner.

“I can’t,” Riggs sadly replies.

According to the synopsis for the episode, Riggs’ wild desperation leaves Murtaugh torn between his commitment to his partner and his commitment to his family. But since Murtaugh’s wife Trish (Keesha Sharp), as well as their kids, Riana (Chandler Kinney) and RJ (Dante Brown), consider Riggs as family, it’s likely that they are going to understand if the family’s patriarch decides to put Riggs’ welfare first this time around.

“Lethal Weapon” Season 1 finale (episode 18), titled “Commencement,” airs on Wednesday, March 15 at 8 p.m. EST on FOX. Watch the preview clip below:

Damon Wayans as Murtaugh, Clayne Crawford as Riggs Murtaugh (Damon Wayans) tells Riggs (Clayne Crawford) to let go of his past in the preview clip for Season 1 finale of “Lethal Weapon.” Photo: FOX/Ray Mickshaw