One Tree Hill is an American television series created by Mark Schwahn for The WB in 2003. After its third season, The WB and UPN merged to form The CW, which is the current broadcaster for the show in the United States. Schwahn serves as executive producer while also writing and directing for the show, including the premieres and finales of all seasons.The show began with nine main characters in its first season. Since then, characters from that first season have left the show, with new main characters having been both written in and out of the series. Originally, it followed two half-brothers Lucas and Nathan Scott who started out as enemies but later formed a close bond as brothers.