After Belthasar was transported through time in 12000 BC by Queen Zeal, he ended up in 2300 AD. At first, the Keeper's Dome can only be reached by going through the Abandoned Sewers, but the party can later get to it by simply flying the Epoch there. When the party enters the dome, they come across Belthasar and an apparently robotic Nu referred to as the Strange Construct. At the back of the main room, there is a sealed door that the party cannot get to until visiting 12000 BC and charging up Marle's pendant with the Mammon Machine. After doing this, the party comes back to the Dome to obtain a time machine, and when they arrive, only the Strange Construct is at the Dome, sleeping by a computer. After opening the back door with the pendant, the group learns many things that Belthasar knew. After going through a final door at the end of this room, Crono and friends come across the time machine Gaspar spoke of, Belthasar's Wings of Time. The Construct comes in the room and puts the final part of the machine on it, also revealing that it is Belthasar's consciousness in a robotic body. After christening the machine the Epoch, the party heads back to 12000 B.C. After Crono is killed by Lavos, the party comes back to the Keeper's Dome with the Chrono Trigger, seeking advice on how to raise the dead. Belthasar tells them to get a clone of the person to be revived from the magician Norstein Bekkler, who is found at the Millennial Fair in 1000 A.D. When the crew report back, Belthasar gives them three Poyozo Dolls and tells them to head to Death Peak, also telling them to turn off his robotic body. The Keeper's Dome has not visited again in the game.