The Silent Killer

Plot:

Digger Barnes returns to Dallas and collapses in Cliff's apartment which is followed by a visit to the hospital and it's revealed that Digger carries a neurological disease that turns out to be hereditary. Although Cliff and Pam are fine, any children that they may bear have a lower-than-normal mortality rate, which puts Pam's marriage to Bobby in jeopardy and Cliff wonders about his son... John Ross Ewing III.