This is a clip from "Legacies", the 15th episode and second season finale of TNT's 2012 revival of the CBS 1978-91 landmark drama "Dallas". This episode aired on April 15, 2013.
Under the guise of having a vacation in Mexico, Cliff Barnes (Ken Kercheval) and his daughter Pamela Rebecca Barnes Ewing (Julie Gonzalo) settle into their hotel room. Realizing that something is up when Christopher (Jesse Metcalfe), John Ross (Josh Henderson), Sue Ellen (Linda Gray), and Bobby Ewing (Patrick Duffy) shows up in the room, Cliff demands to know what is going on.
Bobby reveals that he has been waiting for this moment for a long time: the end of the Barnes/Ewing feud. Christopher steps up and reveals that he went to Zurich and found out the truth about his mother, the original Pamela Barnes Ewing: she died from cancer in 1989. He also reveals that he learned the truth that Cliff had paid off the doctor she was living with to not tell the Ewings that Pam had died, so Cliff would have sole ownership of Barnes Global (the original Barnes-Wentworth Oil Co.). Chris then reveals that he now owns his mother's share in the company, along with John Ross and Pamela, who tells Cliff that she is now married to John Ross (Cliff's worst nightmare), making Cliff the minority shareholder in his own company.
Pamela then reveals that she conspired with the Ewings upon finding out the truth that Cliff had sabotaged Chris' methane oil rig, which caused an explosion that killed her twin babies. The police then enter the hotel room to arrest Cliff Barnes for the murder of J.R. Ewing (The Ewings and Bum, per J.R.'s letter to Bobby, set up Cliff and his partner Harris Ryland for the conspiracy). Cliff is taken away by the police, all the while maintaining his innocence that he did not kill J.R.