S2.E33 ∙ The Hey Arnold Theory - Is Helga the Protagonist?

In 1932, the Japanese Army investigates a mysterious meteorite crash in Manchuria, and discovers a strange material that produces a previously unknown kind of energy. The mineral is later used during the Second World War to power a massive submersible battleship Ra, which is built to revitalize the war effort. Shortly before the launch, a young woman named Annette approaches the officers of the Ra and implores them not to use the battlesub. She says the material was sent by subterranean humans to test the surface dwellers right to live, and by using it as a weapon of war they are sealing the human race's fate. The Ra is launched in the twilight days of the war, and shortly after the bombing of Hiroshima the Ra encounters the American battlesub Liberty, whose crew has been tricked into fighting the Ra by Annette's former partner and friend Avatar, whose appraisal of the human race is much more negative than her counterpart. Annette stops Avatar with a blast of mental energy, but the Ra and Liberty destroy each other. Annette and the Ra's first officer are the only survivors. Fifty years later, an unaged Annette and the grandson of the Ra's captain, Go Arisake, are part of a UN team sent to investigate microwaves being generated at the South Pole. It proves to be a prelude to a massive attack from below the Earth, led by Avatar, that will culminate in the complete destruction of the surface humans. However, Go discovers his grandfather's old ship has been found and rebuild as humanity's last line of the defense, commanded by his believed to be dead father, as the final battle to defend Earth begins.

A psychic orphan is taken in by the powerful Taira Clan. Unfortunately, what she predicts is a future filled with violence and civil war.

Soldier Klaus von Wolfstadt becomes a knight to enemy commander Taki Reizen, leading to a strong romantic bond tested by conflicts.

Three aviation focused war stories of Axis participants.

Taking place in the year 1937 on the eve of World War II, the story involves a mysterious spy training organization known as the "D Agency." The organization is established by Lieutenant Colonel Yuuki from the Imperial Japanese Army. His ideals lead him to recruit people beyond military academy graduates and personnel, while training them to become skilled agents in arts of manipulation. These agents would become a specialized team to conduct operations. One such antihero agent, under the name Jirou Gamou, goes on a harrowing mission to uncover secret documents titled "Black Notes," while battling forces from within and without his own ranks.

The Japanese AEGIS Destroyer "Mirai" of the Japanese Maritime Self Defense Force is on its way to Pearl Harbor for training missions when it's suddenly engulfed in a strange electrical storm.