The story opens with Wild Joe, a bounty hunter, going after the head of the wanted criminal Gill Bastar. It is shown that Gill's huge bounty is due to his killing of many people in self-defense. Ironically the more people he kills, the more he must kill to protect himself.
Wanted! is a one-shot manga by Eiichiro Oda, produced during his senior year of high school in 1992. It was submitted under the pseudonym Tsuki Himizu Kikondo to the 44th Tezuka Awards and won Second Class, earning Oda ¥500,000 and marking his debut in the manga industry.
Per convention at the time, Wanted! was collected with its fellow winners in a single Mezase Mangaka volume, published in early 1993. After One Piece brought Oda to new prominence, it was reprinted in the September 1998 issue of Akamaru Jump, followed by a self-titled collection dedicated to one-shots from Oda's early career.
(Source: One Piece Wiki)
