Dark Seed II is a sequel to the adventure game Dark Seed. It features the further adventures of Mike Dawson in the "Dark World", based on the artwork of H. R. Giger and designed/written by future James Bond novelist Raymond Benson.
Mike Dawson saved the world from the 'Ancients' in Dark Seed, but the experience causes him to have a mental breakdown. In attempt to regain his sanity he returns to his childhood home town of Crowley, Texas, and moves in with his mother. A year goes by, and Mike is still suffering from serious mental problems and memory lapses. To make matters worse, his high school girlfriend, Rita, is found murdered after their high school reunion and everyone seems to believe that Mike is the murderer. It would seem that the 'Ancients' have returned, and in order for Mike to clear his name he must venture through different realities, solve puzzles and stop the Ancients from taking over the world.
Source: Wikipedia, "Dark Seed II", available under the CC-BY-SA License.