After examining the situation, the crew realizes that the ships they passed are part of the Imperial Japanese Navy and that they have somehow been transported back in time more than 60 years to June 4/5, 1942, the first day of the Battle of Midway.

With the Mirai's advanced technology and weaponry, which is far superior to anything possessed by the United States (or any other nation) in this era, the crew realize that they could potentially alter the course of the Second World War.

The struggle of the crew from a modern, peaceful, and wealthy Japan to resist the nationalistic appeal of defending their country, knowing that in this time it is ruled by a brutal, totalitarian and militaristic government is the central theme of Zipang.

Commander Kusaka, who would have perished in the normal timeline, causes unstoppable and devastating changes in the past when he seeks to create a stronger Japan no matter what the cost.

Written and illustrated by Kaiji Kawaguchi, Zipang was serialized in Kodansha's seinen manga magazine Weekly Morning from July 2000 to November 2009.

Since a Japan Maritime Self-Defense Force official on active service was involved in the production, some unrealistic scenes were cut from the anime version.