The Planet: A Futuristic Dungeon Core: The Laboratory, Book 7 (Unabridged‪)‬

Conquering the Earth was only the beginning. 

Emma and Anna may have defeated the last foe to their Empire on Earth, but at a terrible price. The planet's atmosphere has largely burned off, and the remaining ecosystems are on the verge of total collapse. The other planets of the solar system offer a new home, new hope, and new threats.