The sixth episode of the anime series, Big O. The previous series is Bring Back My Ghost.
Roger is woken at the crack of noon by Dorothy, who insists on playing a surging, irritating melody on piano whenever she notices he's overslept. Fed up with her attitude and the song she plays, Roger drags her out to the town.
The pair end up at Amadeus, a small basement nightclub. Inside, they hear the beautiful strains of Chopin's "Raindrop". They enter the club and look at the blissed-out patrons. Then the pianist recognizes Roger, and moves to greet them.
The pianist is an android, a fact which seems to surprise Dorothy a bit. Roger and the android, named R. Instro, seem to share a warm friendship, and Roger asks Instro if he'd consider teaching Dorothy how to play. Initially skeptical, Dorothy is swayed by Instro's fond recollection of playing for his "father", the dead scientist Amadeus-- this causes her to remember singing for her own "father", Timothy Waynewright.
Instro is surprised by Dorothy's incredible precision, but resigns himself to honoring Roger's request to teach her how to play "with heart". After the lesson, Roger and Dorothy prepare to depart, but can't help but notice the last patron in the bar speaking to Instro, as if he was the android's keeper.
Roger goes to Dan Dastun to inquire after this gentleman, and discovers that the fellow is a Mr. Giseng, the former colleague of Dr. Amadeus. In fact, Giseng was the sole survivor of a terrible accident involving a soundwave weapon that killed Amadeus and half-demolished his house. Dan reveals that the accident occurred almost immediately after the Paradigm Group cut off funding for the pair of researchers, a coincidence that Roger does not fail to note.
Later, Roger and Dorothy find Club Amaedus closed. Following up on a hunch, Roger takes Dorothy to Amadeus' old house, where the pair encounter a giant robot-- not a Megadeus, but something else. Roger rushes to confront the machine, and discovers that none other than R. Instro is at the controls-- and the robot, Konstanz, is actually a gigantic photosonic weapon! Instro is convinced that he should carry out Amadeus' dying wish-- to destroy the Paradigm Group, which cut off Amadeus' funding and destroyed his dreams.
Roger summons the Big O, and does battle with Konstanz. During this, he insists that Kontstanz and the destruction of the Paradigm Group is not Amadeus' legacy-- rather, Instro and his beautiful piano playing are the last gifts the scientists left to mankind. The android is unhappy and confused, but elects to attack anyway-- and the Big O can't hold up to a sustained attack from the photosonic cannon. But before the Big O is destroyed, Instro hears Dorothy playing "Raindrop" from the ruins of the house. Touched by the fact that he'd succeeded in giving his gift to the other android, he accepts his role as Amadeus' legacy and stops attacking.
This enrages Giseng, whom we discover was behind the whole thing-- disgruntled at losing funding from Paradigm, he killed Amadeus, created Kontstanz from the scientist's research, and waited for the right time to strike the Paradigm Group. But before he can attack Dorothy, the ruins of Konstanz fall on him, crushing him instanty.
Instro is relieved, but still distraught over how close he came to killing so many. He opts to deny himself his own gift, tearing his hands off. But then Dorothy appears and refuses to accept this, flatly stating that he must continue giving her lessons.
As the episode closes, Dorothy is playing "Raindrop" again, under the close supervision of Instro. Meanwhile, Norman winds the grandfather clock (it's about 1pm), and Roger relaxes in bed, listening to the sweet music.
The next episode is The Call from the Past.