From a technical point of view, Heat Lightning was the first episode of the last batch of ATBG episodes ever produced. This means that we see a reworked, more mature Ginger, more detailed animation and a pretty melancholic atmosphere that hangs over all of the last episodes.
Storywise, Carl and the rest of the family cope with a heatwave while Ginger returns to Camp Caprice. While Carl's storyline is quirky and funny (with a brilliant pun when we finds out Dr Dave is staying over at Foutley House), it's obviously Ginger who gets most of the spotlight.
Ginger's storyline is almost non-existent: she goes to Camp Caprice and meets her old boyfriend Sasha. All the rest is speculation, thoughts, opinions and rumours. What makes the episode a treat is the symbolism in it: the weather (obviously), the puns at the 'fairy prince on the horse', the Darren pictures and the Ginger-Lois hug.
Certainly the latter stands for how Ginger has changed over the year: she couldn't wait to leave in 'Summer Of Camp Caprice', now she's clinging to her mother for security.
Top notch episode to watch on a dreary afternoon and to dream away in it's sweltering summer atmosphere.