One day, breaking the peaceful silence of Ayaka City, the giant kaiju, Gurugioboru appears! The giant monster starts to rampage through the city, spitting a heat ray from his mouth. Two brothers, Katsumi and Isami try and escape, but suddenly they are both cornered! Just then, the Rube Gyro and Rube Crystals appear before them! The two brothers will use these items to transform into the giants of light known as Ultraman!
Unlike his younger brother Isami, Katsumi is afraid of the tremendous power he has received since becoming and Ultraman. These two brothers will both have conflicting opinions about their newfound abilities. Their younger sister Asahi though tries her best to cheer them up and make them feel happy again. When all of a sudden another kaiju appears rampaging through the city, Isami gets buried beneath the rubble of the attack, and cannot move!
Isami becomes the science assistant to a girl at school nicknamed Icarus.
A former policewoman from the brothers' childhood comes to town for her yearly visit with the family.
Isami is forced to handle a kaiju on his own while Katsumi is busy, but Isami has been feeling off and finds himself unable to transform!
Isami gets a big head when he gets his photo taken as Ultraman, but situations change when Makoto Aizen reveals himself to the brothers and also transforms into Ultraman!
After getting beat by Ultraman Dark Noir Black Schwarz, and later seeing him on the news saving people, the brothers decide that they need to train to become better Ultramen.
Ushio decides to close the shop for a day so that he can take his children on a picnic, fearing that his sons are growing too independent to live at home much longer.
While the brothers are down and Makoto Aizen is garnering attention for himself, a new player joins from the shadows.
Asahi learns her brothers' secret and rushes them to the hospital, but when the monster starts attacking again, the brothers disregard their own well-being in order to protect the city.
Asahi still can't believe that her brothers are Ultramen and wants to hear it from their own mouths; Ushio goes through his keepsakes after a photo doesn't match his memories.
After being confronted by her father, Asahi storms off. She then ends up making a new friend named Saki who leaves behind two Ultraman crystals.
The brothers wonder if there is someone other than Makoto Aizen that they should be worrying about; Asahi starts to question her existence.
Asahi has taken off and the rest of the family is both super worried and questioning her existence; Saki forces Makoto to step down from Aizentech.
Asahi and her friends are searching for a place to have their Halloween party when they stumble upon a house with real monsters inside.
With the news that the Earth will explode soon, a group of aliens decide to film a documentary on Ushio and low ratings cause things to spin out of control.
D.R.L.N. has gone rogue and sends out a robot that kidnaps Asahi. Katsumi and Isami must now trust Saki in saving their sister.
After the brothers have their gyros taken, Asahi retells Saki's story to them; Saki tries activating three gyros at once.
Saki brings the Minato family a box of treats and then tells the brothers the truth about their mother in hopes that they'll fight her.
The matriarch of the Minato family has returned from another dimension and asks her boys to retrieve Saki's gyro.
Mio uses the three gyros to trap Leugocyte into a crystal, but Saki states that it must be completely destroyed or else he'll just find a way back.
With the city being torn apart, Ushio has taken away the gyros under his wife's orders; Mio tries to break Aizen's password to save the city.
Mio puts a lock on the gyros and plans to sacrifice herself to save the world.