Kouta tries to use his new abilities as Armored Rider Gaim to help out at his part time job, but he only gets in the way. And when Yuuya mysteriously disappears, Kouta wonders if what happened in the forest was real, and now that he is in charge of Team Gaim, it falls to him to lead the group against Team Baron.
整座遭異世界怪物騷擾不寧的澤芽市，假面騎士展開了如火如荼的鬥爭。 這不僅是為了守護鎮上居民，也是為了貫徹自己心中的正義而戰……。 讓他們多次出入戰場的意志究竟是什麼？在他們達到目標後又能獲得什麼呢？假面騎士戰國時代，就此開戰！
