The second season of the Gate anime adapts the Enryuu-hen and Douran-hen arcs.

Some time has passed since humanity drove back the invading forces from what is now known as the "Special Region." In that time, a bustling town has developed within the protective walls of the SDF basecamp, and relations continue to improve favorably.

However, some in the Kingdom still do not trust Japan, viewing them as a dangerous entity, bent on invading and taking over. Although Itami and the others are working hard to make peace with the Kingdom, dark forces are secretly at work attempting to force Japan's hand. Gate: Jieitai Kanochi nite, Kaku Tatakaeri Second Season focuses on the ongoing political struggle between Japan and the "Special Region" just beyond the Gate.

[Source: MyAnimeList]