In the first season of its series that is the 24th entry in the Tsuburaya Productions' long-running Ultra Series. It is an adaption of the video game Mega Monster Battle: ULTRA MONSTERS. It has been approximately 500,000 years since the last series, and all monsters on Earth had gone extinct, marking the end of the monster era on Earth. Humanity had finally advanced to the outer space, and a new era was formed, called the Galaxy Crisis. The crews of Space Pendragon were tasked to investigate Planet Boris after communications on that planet mysteriously vanished. Arriving on the planet, the crew were astonished to find it inhabited by monsters, with every nearby city perished. While forced to wait for reinforcements, the crew must solve the mystery of this planet's background as a monster tamer named Rei, whose past remained mysterious, joined ZAP Spacy in order to learn his past.