Note: I finished the 15 Episode Batch of Monster from UFO Robot from Eps 31 to 45, I'll be taking a breather but I'm considering whether to continue up to Ep. 50 to be on the half way point of the series, or due the 15 Episode Haniwa Phantoms as originally plan. I'm inclining to the former.

Ura Ura was the monster of the week of Ep.39 of UFO Robot Grendizer: it was a Beast that resembles a sauropod, with a yellow bird like head, a red and purple neck and tail, red legs with purple feet, the Saucer Shell comprise the rest of the Body, with a black middle section. It could fire missiles from the the port holes in the shell, as well lassos and lasers from the side canons, spew fire from the mouth and use its tail as a whip. It's vehicle form was the conventional flat disk, it would fly often vertically rather than horizontally (although this position was optional).

After the failure of collecting any sample of Uranium, King Vega orders Gandal and Zuril to find ways to capture the Space Center and the Double Spazer. Since previous attempts to attack and infiltrate have failed, Zuril suggest to go with a surprise attack, by using a Beast to divert Grendizer and Double Spazer with a force attacking the Center and Ura Ura is the beast chosen for the mission. In the meantime, Hikaru competes in a Acrobatic Competition in her school, winning first place. After the competition, Dambei and Goro vouch for her to Daisuke for a good spot in his team, though he express opposition to the matter, in a later conversation with Goro that war is no show or pastime, as the dangers of the enemy attack can happen at anytime.

As Ura enters the Earth's atmosphere, it is detected by the Center: Koji and Daisuke are called into action, with the later talking with Hikaru, shocked by her word of willing to sacrifice her life in the fight, with him immediatelly pushing her away and leaving. Ura arrives on a valley canyon, launching a pod into a cave, and covering the entrance; it leaves and Koji shows up on the D-Spazer and explores the site finding nothing and returns, the Beast flying back into space. The mysterious pod exits on the other side, revealing to contain 3 strike teams on attack craft, flying at low altitude to avoid detection; these are however spotted by Dambei and Hikaru, who were training in the woods and follow them; they later see them spying on the Observatory and overhearing their plans, aaccidentally causing rocks to fall, calling their attention and running from the invaders. Dambei allows himself to call their attention, while Hikaru runs to the Space Center to warn them, with Dambei successfully avoiding them.

Ura Ura then comes back to attack a city, Koji and Duke leave to fight the Beast though Umon warns it could be a trap, with Hikaru watching their departure, while the invaders give up the chase and proceeds with the attack plan. Grendizer arrives and attacks Ura Ura, calling its attention and it follows, Koji on their tail. Once outside the city, Grendizer fights the beast and avoids its weapons, hitting it with hand beam and melt shower. Duke uses Spinning saucers, bashing the beast, making it crashed, then continues his assault with Screw Crusher Punch, though rapidly Ura turns the tables with tail whip and a barrage of missiles and fire breath, cornering Grendizer to a mountain, causing an avalanche that pins it to the Ground - Ura proceeds to bash Grendizer with tail whip.

With his enemy occupy, Gandal orders the attack team to proceed when Hikaru sees them; she takes Duke's bike to make a stand, distracting them with missiles. The scuffle is notice by the Center and immediately goes into Shelter Mode. Back at the battlefield, Koji uses Cyclone Beam on Ura, allowing Grendizer to escape his imprisonment when Umon calls in on the developments with Hikaru and the Invaders. Grendizer joins up with D-Spazer to return, but is stopped by Ura, who lassos them, and fires its weapons barrage at them. Hikaru continues her fight with the invaders, successfully shutting one attack craft down with the Buggy Saucer. Umon request her to return to the Observatory, but the invaders block her path shooting trees: Hikaru jumps the blockade from the Duke Buggy itself with her acrobatic skills, before the Invaders destroy it (RIP, Duke Buggy!). Hikaru takes refuge in the facility and arms herself with a riffle as the invaders try to meltdown the entrance.

Ura drags D-Spazer Grendizer, smashing it with the ground and mountains: Koji takes the Jet full power and holds back as Duke fires Spin Saucers, cutting the lasso. Regaining flight, they make their final assault on the monster, repelling its attacks with Hand and Cyclone Beams; Koji then fires Double Cutter, decapitating it, the body crashing to the ground. Duke disposes of the rest of the Beast with Space Thunder, and the duo separates to fly back to the Center, where they dispose of the remaining invaders on time.

Later, praising her help in saving the Observatory, Hikaru is effectively welcome as the third Member of Team Grendizer, much to the joy and support of her father.