In the next episode of "Lethal Weapon," Martin Riggs (Clayne Crawford) struggles to come to terms with his dad Nathan (Rex Linn) and his dark past.

The trailer and promotional photos for the upcoming installment, titled "Funny Money," were just released recently, and they show Martin in his psychiatrist's office talking about his father. The doctor asks why he thinks his dad called him from jail. He answers in an unsure tone, "He wants me to come see him."

Apparently, Martin and his dad had a falling out, and since then, he has not seen his father in prison. It turns out that Martin has not forgiven Nathan for mentally tormenting him when he was a child. His best friend protected young Martin from his dad when he shot the old man with a gun.

Martin remembers that fateful day and appears not to have gotten over his dark past. His friends are all concerned about his well-being including Molly Hendricks (Kristen Gutoskie) and his police partner Roger Murtaugh (Damon Wayans).

"What's going on with you? Why does it feel like I'm not going to see you when you come back?" Hendricks tells the troubled cop. He leaves the house to go visit his dad in jail. However, he is not in his right mind. "Hi dad, when you get out of here, I'm going to kill you," Martin warns the elderly prisoner.

In the last episode, a good friend of Murtaugh named Diego Cabrera (Eddie Ramos) was murdered, which put the cop's vacation on hold. He decided to investigate the homicide along with Martin instead. In the end, they were able to capture the culprit who happened to be a wealthy businessman and was involved in drug-dealing.

"Lethal Weapon" season 2 episode 11 will arrive on Tuesday, Jan. 2, 2018, at 8 p.m. EST on Fox.