Gate: Weigh Anchor is a sequel series of Gate: Thus The JSDF Fought There. The plot will be focus on the Japan Maritime Self-Defense Forces (JMSDF) force unlike the ground force in the previous series and Yoji Itami will return as a main character and as a captain of the JMSDF. The new mission for Itami is to travel the seas of the Special Region aboard the Oyashio-Type submarine Kitsashi.
The ‘Gate’ opens again after the otaku Captain Yoji Itami (previously second lieutenant) made a successful connection with the other world. As the Japanese government tries to keep the monopoly on the ‘Gate’, they send the JSDF to the other world to build a good relationship with the people there. Captain Goro Eajima of the JMSDF goes together with the petty officer Tokujima, his subordinate and former cook, on a mission to explore the other world. At that time, an American journalist gets abducted and Edajima and Tokujima get send on a special mission to rescue the journalist. They both board the Oyashio-class submarine ‘Kitashio’ and sail the seas of the other world. But there they get mixed into various problems of the islands and the pirates.