在这部钢铁神杰克剧情/动作/科幻片中,『鋼鉄ジーグ』から50年後の2025年。九州全域は50年前に発生した謎のゾーンに覆われたままになっていた。
その九州に近い下関にハニワ幻神（げんじん）が再び出現。草薙剣児は鋼鉄神ジーグのパイロットとなり、幼馴染の珠城つばきや親友の美角鏡らと共に新ビルドベースの下、妃魅禍率いる邪魔大王国に戦いを挑む。
The story of Kotetsushin Jeeg takes place fifty years after the original and features a new cast of characters - primarily the new main character Kenji Kusanagi, a high school student and motorcycle racer who becomes Kotetsushin Jeeg to fight the sudden reappearance of "Haniwa Genjin" ("Haniwa Phantom Gods", or clay robots) from the Great Jama Kingdom ruled by Queen Himika. Other characters include Tsubaki Tamashiro (granddaughter of Miwa Uzuki) and Kyo Misumi, Kenji's partners. Other main characters from the original series also appear.
