An old secret about the deceased wife of Riggs (Clayne Crawford) when he takes trip down memory lane when he visits his father-in-law in prison in the next episode of the buddy cop action comedy-drama television series based on the film series of the same name "Lethal Weapon."

In the upcoming installment titled "Diggin' Up Dirt," the synopsis from TVGuide also reveals that Murtaugh (Damon Wayans) will be trying to impress Captain Avery (Kevin Rahm), while Trisha (Keesha Sharp) and Leo (Thomas Lennon) try and solve a murder case when they are united by a mutual friend. 

The promo for the next episode centers on Murtaugh looking to prove to Avery that he deserves a promotion. He is seen taking on criminals, blowing up a car in the process. "You should be asking me to be the captain," he tells Avery who appears dumbfounded. It seems as though Murtaugh is aspiring to move up the ladder and take on more responsibilities. 

Murtaugh is also shown trying to assert his authority to his laid back partner, Riggs. Back at the office, he tries to push his weight on Riggs in saying, "That was not a request." However, his partner responds by laughing in his face and turning around to ignore his supposed order. Whether Murtaugh will actually be considered for a promotion remains to be seen. 

According to Cartermatt, "Diggin' Up Dirt" will provide another chance to see Leo Getz on the series. The episode marks the second time in which Thomas Lennon makes an appearance through the second season. 

In the previous episode, Murtaugh and Riggs were able to catch the criminals responsible for the murder of a professional counterfeiter. It was also discovered that Secret Service agent Peterson (Ernie Hudson) played a part in the conspiracy. The duo was able to bring all the perpetrators to justice.

"Lethal Weapon" season 2 episode 12 will air on Tuesday, Jan. 9, at 8 p.m. EST on FOX.