The plan was to invade Dorok through the Sea of Corruption with 300 Imperial Guard and the combined forces of the Periphery . Kushana's officers believe this assignment is a plot hatched by the Three Princes to discredit Kushana and they urge her to attempt a coup. Kushana shrewdly rejects a coup realizing it is a set-up .
Rather than land, Kushana continues on mission, heading straight South to cross the Sea of Corruption  in order to prevent the Periphery Forces from rebelling and tie the gunships to their barges.
The Periphery Campaign ends in a Dorok trap in the Battle of the Acid Lakes . The Torumekian and Periphery Forces are defeated but Kushana continues into Dorok with a much-reduced force, including Nausicaä.
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