For centuries, there has been a war between humanity and the Gedoshu, creatures who emerge from the depths of the underworld and cause fear and terror to those around them. To fight against these creatures, the Emperor of Japan ordained five clans of samurai to fight against the Gedoshu threat three-hundred years in the past, forming the Samurai Sentai Shinkenger. These samurai possess the abilities of "Mojikara", which allow for them to manipulate the kanji (Chinese characters) of the Japanese language to draw upon abilities and ordain themselves with the elements to fight the threats. They likewise utilize "origami" (folding gods) to fight against these creatures "second life", which turns them into giants which rampage through the nation. For 17 generations, the war between the Shinkenger and Ayakashi continued, with slight reprieve given due to a massive sacrifice of the former leader to temporarily stop the Gedoshu leader, Dokoku Chimatsuri. However many years later, with the Gedoshu beginning their attacks again and Dokoku rerising to flood the world with the water of the Sanzu River of the underworld, Takeru Shiba, the 18th Shiba Clan leader, must gather his retainers again to fight back against the threat and protect the world. However, as this generation faces the toughest threat from the Gedoshu yet, a dark secret may cloud over the Shinkenger as the war rages onwards.