Sequel to Diamond no Ace: Act II.

Takumi, a gifted chef, was just let go from his job. He lands a gig at an old boarding house called Astro-sou but hesitates to accept after learning he must also live there full-time. That is until he meets the beautiful and charming caretaker, Mira, and he is sold. The two begin to work together, and their connection deepens. But Mira has a secret: she is not from this world! (Source: Crunchyroll, edited)

When aliens plan to invade Earth, a young boy named Kouta must team up with a giant robot from outer space, Exkaiser, in order to save the world and his friends.

A huge space monster appeared in a city and began to destroy the city. People were escaping with screaming. Among them, there were five high school students, En, Kai, Shin, Yoku, and Ryu. However, they failed to escape, and they rushed into a patrol car parked nearby. The monster was approaching to them. When they began to accept their death, the patrol car glowed blue white and disappeared into a mysterious space carrying them. When they were astonished, it was an alien that appeared in front of them. He was a Bravian who is an officer of the Space Police Organization that was responsible for the peace and order of the universe. He explained them that he was aimed at by ferocious aliens in the Space Prison Sargasso. He added that he had given them a battle machine Dag Beagle made by copying machines on the Earth in order to fight against Sargasso. They turned into Dagwon by the power of Bravian, and fought against space monsters. At that moment, the patrol car came in front of En. En grew into the car and turned into the Brave Robot Dag Fire, then beaten the enemy. However, the fight between the Brave Dagwon and the felonious aliens of Sargasso had just begun.