The final scene in "Exile", which extended into the opening act of "Phoenix", was the establishment of a storyline that would run the course of the third season, and even extend further into season five. The storyline involved Jonathan making a deal with Clark's biological father, Jor-El, to be given powers strong enough to bring Clark back home; the result was a heart attack for Jonathan later in the season, whose body could not handle the powers. Gough and Millar wanted to be able to provide answers for certain aspects of the Superman mythology, in this case it was Jonathan's heart condition. According to writer/executive producer Mark Verheiden, the idea of having Jonathan suffer a heart attack came to the writing team in season one. The story was almost used in season two's "Fever", but they finally settled on an appropriate story in season three that would tie Jonathan directly to Jor-El when he made a deal to bring Clark home that would eventually lead to a heart attack in the episode "Hereafter".