Like other Half-Life 2 episodes, Episode Three will follow the adventures of Doctor Gordon Freeman. Parts of the episode will likely be set farther north, possibly in Arctic conditions. Valve has said that they intend for each episode to highlight a major new feature or gameplay design element. In Episode One, this was the interaction with a well developed NPC, along with full implementation of the Source High dynamic range rendering (HDR) lighting system. In Episode Two, this was creating large outdoor environments, battles previously unseen in the Source engine, performance and rendering enhancements to the Source engine to accommodate multi-core processor architecture and a new cinematic physics system to create large physics-based events. The new gameplay and Source engine features for Episode Three have neither been announced nor discussed by Valve to date. It has been stated that Episode 3 will be the final Half Life 2 episode, but not the end of the Half Life series