New Getter Robo is a 13 episode OVA series made in 2004 as a remake of the original manga. This marked Ken Ishikawa's last involvement in Getter Robo anime before his death. It combined elements from the original manga and anime, Getter Robo G, and the Shin Getter Robo manga.
Oni thought to only be from old legend have been appearing throughout Japan. Dr. Saotome, a researcher in the mysterious Getter Rays had started to create the Getter Robo to fight back against them. He just has to find the necessary pilots first. The first recruit was a street fighter in Shinjuku named Ryoma Nagare who gets wind of the Oni and joins in the battle to fight the Oni. The second was a terrorist named Hayato Jin who gains an interest in the Getter Rays. The third was the warrior monk Benkei Musashibō who owns a sword used by the legendary figure Minamoto no Raiko.
Together they face the Oni while delving into the mysterious power of the Getter Rays. Eventually they are sent back in time to the Heian Era where Raiko is and is in battle with the controller of the Oni, Abe no Seimei. With help from Raiko, the Getter Team manages to defeat Seimei but back home three years after their disappearance with a new lab things start to take a turn for the worse. During a test for an upgrade to the Getter, Ryoma is transported to an apocalyptic future where his friends have become fused with Getter Machines and are attempting to get the power of the Getter Emperor. After being brought back, Ryoma leaves the lab but Seimei returns in the form of a powerful Oni. With Seimei on the loose, Ryoma pilots the Getter again to fight back and manages to destroy Seimei.
After the battle some of the others start to doubt the Getter's power but with the threat of the Oni still present there are disagreements. Suddenly the ones who guided Seimei and the Oni appear, the Four Heavenly Kings. They attempt to destroy the Getter as it could destroy the planet and is a threat to them. The Getter Team face against them in a type of subspace while keeping the Getter Rays in check with three of Kings destroyed and their leader Tamonten destroyed by the appearance of the Getter Emperor. Wanting to fight against the Emperor and any other machine who tries to take that form, Ryoma leaves to combat them while the others go back home and think about the loss of their comrades.