Former soldier Shingo Hojo, French spy Remy Shimada, and Bronx gangster Killy Gagley aren’t exactly your “hero of justice” types. They’d rather be flirting, bantering, and goofing off than battling evil. But when the malicious worldwide organization Docooga attempts to steal a new, powerful form of energy called Beamler, they’ll take up arms to fight them... in the awesome giant robot, GoShogun! Now pursued around the world in their teleporting carrier Good Thunder, GoShogun’s piloting team must keep Docooga at bay while foiling their eccentric enforcers, righting wrongs they come across, and occasionally facing ghosts from their own tragic pasts. It’s an unexpected combination of drama, satire, and giant robot action like nothing you’ve ever seen before!

The shogun Mito Mitsukuni crosses Japan in disguise, accompanied by two bodyguards, the master swordsman Suke (Sasashi Sukesumaburo) and the strongman Kaku-san (Atsumi Kakunoshin), the grandson Sutemaru, the dog Dombee and, in part of the series, by a girl named Yuki. Each episode follows a basic plot: the group arrives in a village, with the shogun hiding his identity. While they're resting they happen to witness some mysteries and some wrongdoings done by local personalities, prompting the group to investigate. In the end of every episode Suke and Kaku confront the main evildoer and, after a brawl in which Suke and Kaku show their physical prowess besting the minions of the main perpetator with their abilities (Suke valiantly fighting with his katana, Kaku showing off "the strenght of 100 men" to overcome his enemies), Suke shows the inr? that reveals Mitsukuni identity, ordering the villains to surrender and accept Mitsukuni's judgment, who then explains the mystery as an act of deliberate evil, punishes the wrongdoers and encourages the good people to go on with their lives.

11-year-old Kenichi Mitsuba is an average kid who goes to secondary school and struggles with his studies, he is very stubborn and is very lazy and therefore always ends up frustrating his parents and teacher. He loves to find an easy way of things. He befriends Hattori Kanzo, a ninja from the Iga Clan, and he becomes part of the Mitsuba family along with his brother, Shinzo and his ninja dog, Shishimaru. Hattori helps Kenichi with his problems, and constantly keeps an eye on him, as a good friend. The main antagonist Kemumaki, a Koga ninja and his ninja cat, Kagechiyo always troubles Kenichi, mainly because of their feud over one girl, Yumeko. Kenichi asks Hattori to take revenge as a recurring storyline in many episodes. Although Hattori is a good friend, Kenichi sometimes fights with Hattori due to misunderstandings created by Kemumaki. Sometimes Jippou, Togejirou and Tsubame help him.

Shin Dokonjou Gaeru est la suite directe de la série TV animée Dokonjou Gaeru.