Hilarious and fascinating anime series adapted from Mari Yamazaki's award-winning manga. It follows Lucius Modestus, a renowned bathhouse architect in ancient Rome during the reign of Emperor Hadrian, who is suffering from a creative block. By a twist of fate, he discovers a hidden time-slip portal at the bottom of a Roman bath that transports him to contemporary Japan. Amazed by the sophistication of Japanese bathing culture (sento and onsen), Lucius returns to Rome to apply these incredible ideas, revolutionizing the empire and earning imperial favor.
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Baths of Caracalla — The Splendor of Roman Engineeringconfirmed
One of the largest and most spectacular public bath complexes of ancient Rome, built in the 3rd century under Emperor Caracalla. Capable of hosting thousands of bathers, it featured magnificent mosaics, libraries, and gardens. In the series, it represents the pinnacle of classical thermal architecture and serves as the grand benchmark from which Lucius draws inspiration to design his monumental public projects in Rome using sophisticated hypocaust heating systems.
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Hadrian's Villa (Tivoli) — The Emperor's Thermal Retreatconfirmed
The majestic and lavish imperial villa built by Emperor Hadrian in the 2nd century in Tivoli, east of Rome. It is a vast archaeological complex blending Roman, Greek, and Egyptian architectural styles. In the series, it is the setting where Lucius is personally commissioned by Emperor Hadrian to design an exclusive, private bathhouse, allowing the weary ruler to relax and contemplate the future of the Empire far from the intrigues of the Senate.
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Stabian Baths (Pompeii) — A Lesson in Classical Designconfirmed
The oldest and best-preserved bath complex in the historic city of Pompeii. It perfectly showcases the classic layout of Roman public baths, divided into the changing room (apodyterium), cold bath (frigidarium), warm bath (tepidarium), and hot bath (caldarium). In the series, Lucius visits them to study traditional proportions while scheming how to integrate the amazing conveniences he discovered in modern Japan.
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Sento Inari-yu — The Time-Slip Gateway Sentoconfirmed
A historic, traditional public bathhouse (sento) built in 1930 in Kita-ku, Tokyo, and designated as a National Tangible Cultural Property. Its grand wooden facade resembles a traditional Buddhist temple. This is the exact visual inspiration for Lucius's very first time-slip, where he wakes up completely bewildered by walls painted with Mount Fuji, push-button hot/cold taps, and the iconic yellow "Kerorin" basins.
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Kusatsu Onsen (Yubatake) — The Steaming Soul of Gunmaconfirmed
Renowned for its highly acidic water and extraordinary therapeutic properties. Its undisputed symbol is the "Yubatake" (hot water field), where spring water flows through historic wooden cooling chutes. In the series climax, Lucius is inspired by the perfect communal layout of this hot spring town and the traditional Yumomi ritual (stirring water with wooden paddles) to design a grand Roman thermal resort.
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Sekizenkan Ryokan (Shima Onsen) — The Temple of Wood and Healingconfirmed
Founded in 1691 in the mountains of Gunma, this is the oldest surviving wooden hot-spring inn (ryokan) in Japan. Its Genroku-style main building features elegant Romanesque arched windows and exudes mystical beauty. The peace of its healing waters and traditional architecture inspire Lucius about the value of bathing as preventive medicine and spiritual rest.
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Kita Onsen Ryokan — The Wild Tengu Hot Springsconfirmed
A historic mountain hot spring lodge in Nasu (Tochigi) with over 160 years of history. Famous for its open-air pool and the indoor "Tengu-no-yu" bath, presided over by massive wooden Tengu masks. Its rustic, secluded atmosphere surrounded by raw nature inspires Lucius to transition away from Rome's marble luxury and create open-air baths seamlessly integrated with rocks, forests, and wild streams.
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Hakone Kowakien Yunessun — The Theme Park of Bathing Funconfirmed
A large and vibrant hot spring theme park in Hakone that challenges traditional rules with its playful, aromatic baths of red wine, espresso coffee, and green tea. In the series, this jovial and playful atmosphere directly inspires Lucius to revolutionize Roman public baths, creating recreational sections where commoners and patricians enjoy novel fragrances and colors together.
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Dogo Onsen Honkan — The Ancient Communal Bathhouseconfirmed
Mentioned in imperial chronicles dating back over 3,000 years, Dogo Onsen is one of Japan's oldest and most revered hot springs. Its iconic three-story wooden main building, crowned by the Shinrokaku tower with red stained-glass windows, is a national treasure. In the series, its vibrant community-centric atmosphere inspires Lucius about the true democratic purpose of public baths: to be the heart of urban life, bringing all citizens together under one roof.