When it is uncovered that Digger has a fatal genetic disorder, Cliff worries that he may have passed on the faulty gene to John Ross if indeed he is the father.

Kristin begins to pursue J.R. romantically after he gives her a summer job in his office. Meanwhile, Bobby learns the truth that Pam is pregnant before she makes a decision about having an abortion due to the risk of genetic defect.

As Bobby bonds with the ranch hand's son, Pam informs him that their unborn child may have a fatal genetic defect. Meanwhile, J.R. hires a man to tail Sue Ellen.

At the annual Ewing rodeo, Sue Ellen develops a crush on Dusty Farlow, a cowboy, and Digger uses the event to find time to see John Ross.

Miss Ellie must cope with Jock and Lucy's poor reaction to her mastectomy. Meanwhile, Sue Ellen meets up with Dusty at a hotel.

Much to Kristin's surprise, J.R. convinces Alan to marry Lucy.

Digger admits to a reporter that Cliff is the father of John Ross. After the news breaks, a series of custody suits lead to a blood test that determines the paternity of John Ross once and for all.

J.R. tries to convince Alan and Lucy to relocate to Chicago, but Jock works to find Alan a law partnership in Dallas.

Cliff investigation of the body found on Southfork leads him to suspect that Jock is to blame.

Jock goes on trial for murder. Sue Ellen begins drinking heavily to deal with Dusty's death.