Super Dimension Century Orguss - Season 1 Episode 9 Revolution

The Glomar is hovering above a battlefield, where they meet some survivors, rebels led by Jann who asks the Emaan to help them overthrow the aristocracy. The Emaan already made a contact with Ann months ago, lending her a powerful weapon called the Hasai Cannon. They didn't expect Ann will use it to suppress the peasants, so they agree to help the rebels overthrow Ann and get the weapon back.