The story begins after Earth is destroyed. There is some iconic concept art in the article like this Planet of the Apes style shot of the Statue of Liberty covered by trees.
Events in the game take place 1,000 years after post humanity where monsters and guardians reside on the planet. Famitsu has pictures of those, but no details on how Earth Seeker plays. Kadokawa Games, the company publishing Metal Max 3, another post apocalyptic game for the Nintendo DS, has Earth Seeker slated for release this winter.