The Adventures of the Galaxy Rangers

The Queen has built a cannon that can destroy a planet, and is trying to hold the League hostage with it. The Rangers are sent in to work with the resistance group on the planet and destroy the weapon. The resistance group is led by Wirwar, whose family is held hostage by the Queen and who tries to free them by handing the Rangers to the Queen. Despite that, they succeed in destroying the Queen's weapon but have to escape in a ship which they discover only has five minutes worth of oxygen.