When a variety of circumstances leave Nobita, Doraemon and the gang wanting to run away from home, they face the task of finding somewhere to live. However, with every seemingly spare piece of land already owned by someone else, building themselves a house looks impossible – that is, until Nobita has the idea of travelling back seventy thousand years into the past. While the group are making themselves at home in an uninhabited Japan, back at home a glitch in space-time has sent a caveboy crashing into the middle of the city. When they return to the present, Doraemon et al encounter the child – named Kukuru – and take him with them back to their prehistoric paradise. Together, the gang decides to return the young boy to his true time and help him free his captured friends, even if it means facing the dangers of Kukuru’s enemies: the dark tribe.