In ancient Rome, renowned architect Lucius is down on his luck. He has been fired because his style of buildings is unfashionable, and all the bathhouses in the city are noisy, boisterous places that no longer prioritize relaxation. To get some peace and quiet, he sinks below the surface of the water, the only place where his fellow bathers' chatter can't reach him, but a powerful drain pulls him into the depths! Upon emerging, he finds himself in a vastly different bathhouse, and though the architect believes it's just the slaves' quarter, he's actually been pulled through time to modern-day Japan! Now, armed with knowledge of these strange new baths, Lucius is determined to restore his reputation and revolutionize the Roman bathing culture!
Shou Hachiya plays lead guitar for Fab Four, the greatest Beatles tribute band in Japan. But right on the cusp of their big break, the group's lead singer decides to quit due to rising tensions and conflicting goals. In a fit of rage, bassist Makoto shoves the rebellious singer into the path of an incoming train, and when Shou tries to stop him, all three end up tangled and plummeting towards certain death. But instead of dying, they awaken in 1961, the year before The Beatles released their first album. Now, in a world where nobody has even heard of The Beatles yet, the cover band decides to compete with their idols and release a few hits as their own, in an attempt to force the legendary band into creating new and even greater songs.
These two time-traveling seinen manga take the most ridiculous concepts and make them work fabulously. If you liked the historical quirkiness in one, you should appreciate it in the other (though Thermae Romae is much more comedic). The art style is fairly similar as well.