Biker gangs were very popular in 1980's television series, even on sci-fi/fantasy shows like Galactica 1980 and V: The Series, and this episode is basically their Biker Gang Episode (hybrid with the Mad Max post-nuclear mutant biker vibe).
Jonna Lee tells the old man their entire story so far... expository dialog for people who were just beginning to watch the series to be caught up.