Lethal Weapon was on the air for three seasons; the first two seasons followed the lives of Roger Murtaugh and Martin Riggs, based on the Lethal Weapon movie franchise. Riggs was prone to pulling insane stunts and taking dangerous risks due to his ongoing grief for the loss of his wife and their unborn child.
Murtaugh was more by-the-book and usually horrified by Riggs' stunts. The two together made for an amazing partnership and their tendency to get into trouble created all kinds of action and drama for the show, making for some explosive and memorable episodes.
"The Murtaugh File" (8.4)
While investigating a murder, Riggs and Murtaugh discover that the victim was the boyfriend of Dr. Cahill (Jordana Brewster). As they dig into the case, they discover that someone is stalking Cahill and they organize a protective unit for her.
Riggs and Cahill bond and he winds up saving her from her stalker and her exploding home by diving into her pool. In the meantime, Murtaugh is exasperated at Riggs' persistence in finding out why Murtaugh has a file in Cahill's office. By the episode's end, Cahill tells Riggs that he'll have to see another doctor, but Riggs doesn't take the news well and resorts to some dangerous measures to prove his point, making for a sweet moment between doctor and patient, and showing just how much Cahill really is helping Riggs.
"An Inconvenient Ruth" (8.5)
After he's referred to as a "grandpa" on the playground while out with his wife and youngest daughter, Murtaugh tries to prove a point and winds up stuck in a slide. Afterward, he takes several dangerous risks to prove his age doesn't limit his abilities.
Elsewhere, Ruth, a witness that intervened in a jewelry store robbery by shooting one of the burglars, becomes a pain in the butt for Riggs. Riggs is already at his limit, fearing that now that he's sober, he's lost his edge without alcohol. Ruth annoys and blackmails Riggs, though the two eventually wind up bonding.
"Can I Get A Witness?" (8.5)
While investigating a casino heist, Riggs develops a relationship with a young boy named Ethan, who was a witness to the heist and who later ends up in Riggs' care when the criminals responsible shoot his mother and she winds up in the hospital.
Ethan comes to truly depend on Riggs, and Riggs ends up saving Ethan's life in a shootout at Riggs' trailer when the criminals come after the young boy. Plus, Riggs finally decides what to do with the check he received for the sale of his home in Texas, gifting it to Ethan and his mother so they can get a new start. Elsewhere, Murtaugh is bent out of shape by everyone finding it hard to see him as a "motorcycle guy" and frequently tries to prove himself as one, which leads to a motorcycle purchase.
"A Problem Like Maria" (8.6)
Plenty of action takes place in this Season 1 episode. Riggs' and Palmer's relationship is gradually picking up. He's in for a good scare when Palmer later turns up missing, and the man he saw her speaking to in the parking lot before she left winds up dead.
Riggs and Murtaugh work to track her, a baby, and the baby's mother, Maria. Once they do so, the trouble doesn't stop there, as the cartel is intent on grabbing the baby. When all is said and done, Palmer also discovers that one of the men they dealt with in the cartel may have been responsible for the death of Riggs' wife.
"As Good As It Getz" (8.6)
Chaos is everywhere in this episode when Leo Getz narrowly avoids getting killed in a shootout at a donut shop while trying to negotiate on behalf of his newest client. Riggs and Murtaugh manage to find out he was a witness and track him down to protect him from the cartel, and find themselves paired up with DEA agent Karen Palmer once again.
As sparks fly between Riggs and Palmer, they begin to figure out that Palmer was the target all along, as she was supposed to be at the donut shop at the time of the shooting. Meanwhile, Murtaugh is concerned with Trish's decision to quit her job, but eventually comes to support her. Leo even puts himself and Trish in a bus ad, though Trish isn't particularly thrilled at the idea.
"Jingle Bell Glock" (8.6)
Murtaugh's annoyed with his neighbor's excessive Christmas decorations, which depletes the power grid. However, that's the least of his problems, given Riggs is more disturbed than usual for the holidays, and is provoked by the suspect in their latest case. Riggs has several flashbacks to his life with his late wife, Miranda, including the day they met and another memory in which she told Riggs that he would be a father.
Already drowning in grief, Riggs is faced with the possibility that his wife's death may have been murder, given the suggestions made by Eddie Flores, the suspect in their case.
"One Day More" (8.6)
Riggs' new start is permanently finished in the Season 2 finale. Riggs intends to return to Texas with his girlfriend Molly and her son Ben, but Riggs' father ensures that that doesn't happen. Instead, Riggs' father kidnaps Trish, and Murtaugh and Riggs release Riggs' half-brother Garrett to exchange him for her.
While Trish is saved and Riggs' father is killed, Garrett escapes, which ultimately leads to Riggs' death as Garrett shoots his brother dead before Riggs can leave town to start his new life. The episode was filled with all kinds of tragedy, forever changing the show.
"El Gringo Loco" (8.7)
Picking up two weeks from where the Season 1 finale left off, Riggs is in Mexico and comes close to killing Tito, but is stopped by Murtaugh. Murtaugh talks Riggs into taking Tito back to the United States, but while locking Tito in the trunk of the car, Riggs accidentally severs Murtaugh's finger.
While they were dealing with that, Tito was killed in the trunk, landing the two, as well as Captain Avery back in Los Angeles, in big trouble. Riggs and Murtaugh have their work cut out for them to set things right, and for Riggs to get the justice he wants for his late wife.
"Wreck The Halls" (9.0)
Christmas is once again delayed for Riggs and Murtaugh with the murder of Diego, a friend of Murtaugh's. While Murtaugh delays his Hawaiian vacation trying to clear Diego's name, Riggs tries to have a happy holiday with Molly and Ben, connecting with them both.
The episode even contains close calls for both Riggs and Murtaugh. It's a Christmas that's both merry and scary, considering the Christmas cheer and the fearsome criminals the partners are up against.
"Commencement" (9.2)
Riggs snatches Gideon from a prisoner transport and tortures him for information about his wife Miranda's death, breaking all kinds of laws in the process. Murtaugh even ends up kidnapped and tortured at one point.
Riggs is further thrown into a downwards spiral when he finds out that Miranda's own father had a hand in her death. Riggs eventually heads off to Mexico to look for Tito Flores, and Murtaugh later follows him. The Season 1 finale shows just how deep a bond the two partners share, and how far they would go to protect and help one another.