S3, E3: Cliff Barnes flys his father, Digger, to Dallas to show him how he's getting even with the Ewings but Digger's sudden medical problem places a cloud over Cliff, Pam, and even Sue Ellen's new baby. A doctor's examination discloses that Digger has a genetic disorder that has not only been passed to his children, but also to their offspring,which could prove fatal to John Ewing III if Cliff is actually the father.