Do-ug had apparently been frozen deep within Mount Pacley over 2 million years ago, but when Betrayus caused the mountain to erupt, it released Do-ug from his frozen imprisonment, but he was quickly frozen by Pac-Man who was trying to stop the erupting volcano. Do-ug however was still conscious and when Pac-Man approached the re-frozen cave boy, Do-ug was able to quickly escape and trounce Pac-Man. He then attempted to escape the mountain but was stopped by Pac-Man under Sir Cumference's orders who believed the cave boy would be in danger if amoral scientists were to discover him. After capturing him and bringing him back to the lab, they were able to discover that Do-ug could speak a primitive form of the modern language and found out that he was starving, unfortunately Pac-Man had already eaten all the food in the lab. They then took him out to get the starving cave boy some food, but eventually his secret is discovered and they were forced to flee back to the lab. Once they return, Do-ug admits that he is homesick so the gang decides to use the Pac-a-Chini to take him back to his own time. After arriving 2 million years in the past, Do-ug is ecstatic once more, however the Pac-a-Chini is stolen by Do-ug's tribe, leaving Pac-Man, Spiral and Cylindria stranded. When they found the tribe's village, they tried to ask Do-ug to get it back, however Do-ug admits that he is only a simple cave boy with no role in the tribe, as such he is unable to do anything. Luckily, after Pac-Man fought off a pack of Pacasaurs using his fire berry, the tribe decides to give the trio back the Pac-a-Chini. Before leaving Pac-Man gives Do-ug the gift of fire and declares him "Keeper of the Flame", thus giving Do-ug a role within the tribe and becomes the first Neander-Pac to wield fire. The group then bids farewell to Do-ug before heading back to their own time.