Central focus of episode 3. Harumi is first seen in Episode 2 as Ichi's tutor. She is an "oasis for his heart", clearly an oneesama type to the youth. Although seemingly sweet and professional on the outside, she hides a dirty and disturbing secret within. Harumi suffers from dissociative identity disorder and for unknown reasons has formed a second personality known as Maria.

In this guise, she is apparently an "oasis" for the heart to many more people, in a somewhat darker flipside. Maria, contrasted to law-abiding and "clean" Harumi, is a prostitute who talks much more openly, and even goes so far as to have a completely different speaking dialect. As Maria is a separate entity to Harumi within the same body, they often speak to one another via the answering machine in Harumi's apartment. Identified by a trademark pair of wigs, a (fake) mole and a completely different sense of fashion, Maria lives out her deepest desires, believing them to be the repressed wishes of Harumi. Initially, though Harumi and Maria are at odds, the latter personality wishes the best for the former. This changes, however, as Harumi is offered a marriage proposal from a fellow teacher and begins to desire an end to Maria.

Throwing away Maria's clothing, and quitting her job as a sex worker, Harumi seems determined to start a new life as just herself. However, she begins to receive phone calls from Maria demanding that the latter be set free, and that Harumi is the actual fake personality. Her grip on reality begins to fluctuate rapidly as she begins to blank out often realizing her Maria persona has begun taking her over without her permission, making Harumi do things against her will. As the stress and trauma of this begins to take its toll, Harumi and Maria ultimately fight for dominance over Harumi's body as Lil' Slugger mysteriously appears.

Harumi's family name has the word "Chō" in it, which is a part of the Japanese word for "butterfly." Butterflies are generally viewed as being an ugly creature who turns into a beautiful one, or a symbol of transformation and/or change. Which persona is the butterfly and which the caterpillar, however, is a heavily debated subject. Although, they may in fact each be both, as the bookish Harumi is beautiful on the inside, and, while considered pretty by the other characters, is commonly attributed to being less beautiful than Maria (who is portrayed as being ugly on the inside). Harumi and her episode are often compared to Satoshi Kon's other works, Perfect Blue and Millennium Actress, which included similar themes of a lost sense of self.

(Source: Wikipedia)