Lost July

 is the sixth episode of the Trigun anime.

Summary:

The town throws a party for Vash and friends. The town finally is able to hire engineers to fix their plant, and they arrive on a huge sand steamer. Including the main engineer who is in fact a very gorgeous woman. She hires Vash as her bodyguard/doggy and he follows her around town. The only problem is that someone is after her, and Vash has to fight off a pretty nasty masked guy. The next day our lady takes Vash into the Plant and we find out that she was the one who hired the masked man. Vash defeats him, but then our lady plans to destroy the Plant to kill Vash! He manages to stop the Plant from blowing up somehow, and finds out that the woman had lived in the City of July when it had been destroyed. The people of the city had survived the explosion, but ended up starving to death including her parents and she sought revenge on Vash for it seeing as though he had been the one to destroy the city! But how had he not changed after nearly 30 years?