Todesangst is a single player Half-Life modification, which follows an alternate timeline where the nuclear destruction of Black Mesa and the Seven Hour War never happened. Gordon is back from Xen, and it's all business as usual. That is, until a sinister scientist named Jack Newell, motivated by morbid curiosity and seething hatred of Gordon, decides to start another bloodbath, forcing Gordon and his friend Joe to put a stop to his experiments with Xen creatures. Todesangst (pronounced TOH-dess-ahngst) is a German word that literaly means fear of death, but is usually translated as meaning terror or dread.
Todesangst introduces the new sinister character Dr. Jack Newell, expert chaos theory mathematician and Director of Black Mesa R&D. Gordon Freeman and Dr. Newell have always had an adversarial relationship at best, and Gordon's hero status following the containment of Xen only served to inflame Dr. Newell's hatred and jealousy of him. The timeframe for Todesangst is set shortly after Gordon Freeman's successful return from Xen. The episode opens with a cut-scene of Mr. Blackstone (a.k.a. the G-man) arriving at Dr. Newell's office. As we soon discover, Dr. Newell has had Mr. Blackstone in his control all along, and has his own intentions for the exploitation of Xen's biological uniqueness. . . Its up to you, Gordon, to stop your evil colleague from unleashing the horror of Xen on humanity. . . if its not too late. . .