The first season's storylines include the construction of an oil pipeline, Zach Powers' vendetta against the Colbys, the romance between Jason and his sister-in-law Francesca, the subsequent collapse of Jason's marriage to Sable, and eventually the revelation that Jason, not his brother Philip, is in fact Jeff's father.
In the second season, Jason manages to divorce Sable and plans to marry Francesca, but the presumed-dead Philip reappears alive.