The trainees bond with the precocious Masegaki kids and life at U.A. goes back to normal as autumn approaches, but Aoyama has been acting strangely...

With her closest friends now giving her the cold shoulder, Mikoto feels isolated and helpless, but finds a surprise ally in Kongo. Kongo tries to track down any clues that will lead her to the whereabouts of Mikoto's missing "twin sister."

The first semester has come to a close, and the Ikeda lab is having a party where everyone's bringing what they like to eat and drink. They're having fun, playing games like the "prime number Yamanote line game," when a drunken Himruo finally does a certain something with Yukimura... And even Kanade ends up drunk... On the other hand, the mood quantifier obtained through the previous round-robin kiss experiment has progressed their research tremendously, and in order to gather more data, Yukimura and the others use fairy tales such as "Snow White," "Kaguya-hime," and "The Crane Returns a Favor" as references, but...

Lucius pops up at a hot spring bath right into the middle of a crime scene. The truth comes to light, and Lucius returns to Rome with a new souvenir. Emperor Hadrian asks Lucius to construct a bath that will help him lose weight and feel young again. A trip through the bath brings him to a Japanese day spa.

Marcus goes to see Lucius and finds him in a deep depression. A trip through a cauldron to Japan snaps him out of it, but not in the way he expected. Emperor Hadrian orders Lucius to build a new public bathhouse. While reflecting on it's design, he winds up in a Japanese water park.

Lucius is sent to the base of Mt. Vesuvius, where a new hot spring has been discovered. He slips on a wet rock, and winds up in a hot spring village in Japan.

Lucius starts to consider adding private baths to the floorplan of homes. As if on cue, he is whisked off to the private bathroom of an elderly man in Japan. Lucius's ideas and designs have caught the eye of Emperor Hadrian. On this journey to Japan, he winds up in a bath department store.

Lucius is a Roman architect whose designs aren't appreciated. He couldn't begin to imagine the strange adventure that awaits him. A dying Consul's last wish is for a private bath. While scouting the location, he is transported to modern Japan once more, and discovers more wonders.

Main learns from Frieda that the illness she has is called the Devouring, and that it will flare up if she ever feels anxiety or loses hope. Almost on cue, her fever starts acting up...

Subaru risked his life to save the children from a pack of Ulgarm, but he was so powerfully cursed that there could be no saving him. Even Beatrice is unable to undo the complex web of curses on him, and says he'll grow weak and die within half a day. The only way he can survive is if the entire Ulgarm pack is defeated, but time is not on his side. Subaru is ready to give up when he learns that Rem has gone into the forest by herself... Knocked unconscious by Subaru's attack, Rem dreams of an event in her past that she and Ram would rather forget... a sin for which Rem feels she can never be forgiven. After waking up, she tells Subaru that she's just committed the same sin again. When the three of them are moments from being cornered by the Ulgarm pack, Subaru takes off to draw their attention so Ram and Rem can escape.