Vash the Stampede has a $$60,000,000,000 (read: $$60 BILLION) reward for his capture. That's how Trigun starts out. He meets two women, Meryl Stryfe and Milly Thompson, who claim that that they are from the Bernardelli Insurance Society looking for Vash the Stampede to minimize the destruction around him. They follow him around at first, not know that he is Vash the Stampede. But in Episode 5, they find out (Meryl if really disappointed) that the Vash they were looking for is the one they've been following around.
They continue following Vash around and in the desert, they find Nicholas D. Wolfwood, a travelling priest who carries a HUGE cross with him. Adventures happen around them as the story progresses. Then part of Vash's mysterious past is started to be revealed. We find out that he destroyed July city without killing anyone. With the introduction of Legato Bluesummers, Vash begins to be targeted by the assassin group, Gung-Ho Guns. A flashback to Vash's past reveals that he and his brother, Knives were on a ship with humans from Earth, looking for a new planet. However, Knives despised the imperfect humans and tried to kill them.
Vash and his memory of Rem, a woman on the ship, give him his principle of not killing. However, time after time when each of the Gung-Ho Guns come for him, there is more killing and destruction around him. During his third encounter, with E. G. Mine and Rai Dei the Blade, he destroys yet another city, Augusta. We see that he destroys the city with his gun, which turns into this super particle gun that blew a hole in the fifth moon. He goes on to defeat all of the Gung-Ho Guns and comes at last to Legato. Can he still keep his non-killing principle? What will happen to Vash if he has to fight his brother, Knives? The conclusion of Trigun is so unpredictable that you have to watch until the end!!
This anime series is complete with 26 episodes. I have the manga up to volume 3.