Arale and Tsururin use Senbei's Time Machine to travel back to prehistoric ages and Arale stops a meteorite by Headbutting it and turning it into the Moon preventing the Dinosaur's from going extinct.
Million of years later after Arale stops the meteorite, Astronauts discover hand prints on the moon and declare that there was life, however unbeknownst to them the hand prints belong to Gatchan.
Gatchan goes into a cocoon for 15 days and hatches into two separate beings.
King Nikochan and his assistant hijack Senbei's spaceship he was building and fly back to their home Planet Nikochan with Arale and Gatchan still on board. Arale liberates the planet from a tyrannical alien named Komattachan who took it over during King Nikochan's absence and Arale and Gatchan head back to Earth when Senbei catches up to them.