In 15th century Kyoto before the Onin War, outlaw leader Hyoe uses his deadly swordsmanship to spearhead a rebellion against the corrupt Shogunate and its army, commanded by his former friend and now enemy Doken.
When Japan surrenders at the end of World War II, soldier Hiroo Onoda retreats into the jungles of the Philippines to continue the war himself for another 10,000 days.
11-year-old Yusuke and his classmates camp in the woods and see a strange light. They discover a small metallic object like a robot which talks, calls himself Tetra and knows Yusuke's name....