Lucius Modestus, an ancient Roman architect, is job-hunting because he struggles to come up with new ideas. As his demeanor and personality grow dismal, his friends take him to a bathhouse to help him relax. Unable to unwind in the bustling, crowded bath, Lucius dips his head into the water. Down there, he discovers a secret tunnel that transports him to a modern-day Japanese bathhouse, providing the inspiration he needed for a new creation. Loaded with what seems to be knowledge way ahead of his time, Lucius does his best to recreate his findings, which are usually inferior in quality due to his circumstances. However, the sheer ingenuity may be just enough to gain the attention of the citizens and regain his reputation as an architect.