In ancient Rome, bathhouse architect Lucius (Abe Hiroshi) becomes famous with designing the original "thermae" (bathhouse). He receives an order to build a thermae in the colosseum to help gladiators recover from their wounds, but faces difficulties. Thus, Lucius travels again to modern day Japan through the time slip. He meets Manami (Ueto Aya) again, who is now a reporter for a magazine which covers bathroom. With the help of the flat face Japanese tribe, Lucius again designs a new thermae.
Meanwhile, Emperor Hadrian (Ichimura Masachika ) wants to keep the peace with the thermae, but the Senate wants to extend the land by using force. Emperor Hadrian and the Senate now have a confrontation and Rome becomes divided.