Developer and Steam online distribution system creator Valve Software have announced that announced Half-Life 2: Episode One, the first episodic expansion for the major franchise and one of the first high-budget episodic titles to ever debut, has gone gold for the PC. The episode will be available for purchase over Steam, as well as on retail shelves in North America, on June 1 for $19.95, and Valve's announcement has also revealed more information on new episodes of the episodic trilogy. Half-Life 2: Episode One advances the 15-million unit selling franchise and launches the first in a new, three-part series that is scheduled to conclude by Christmas 2007 - meaning that Episode Three will debut by the end of next year. In addition, the release of Half-Life 2: Episode One will also include a first look at Episode Two, which will ship by year's end. Episode One offers a new single player experience created by Valve, and is designed to be four to six hours in length. The new game will allow players to once again play as Dr. Gordon Freeman as they face the immediate repercussions of their actions in City 17 and the Citadel. In addition to the new single player experience, two multiplayer games are included. Additionally, purchase of Episode One will also include free access via Steam to Half-Life 2: Lost Coast, the interactive technology demo that introduces high dynamic range lighting to Valve's Source Engine. "Given the rapid changes in PC gaming, we expect episodic games will have the same impact on single-player gaming that Counter-Strike had on multiplayer," said Gabe Newell, president and co-founder of Valve. "The frequent releases of upgraded technology and new content works better for both consumers and developers, and is one of the key reasons Counter-Strike grew to be 80 percent of the online action market. We decided that a follow-up to Half-Life 2 delivered in 18 months with our first episode was more in tune with what our customers want than waiting 6 years for another monolithic product."