Reincarnation is the eighth episode of Disgaea: Hour of Darkness.
The episode begins with the song Red Moon playing while the lyrics show on the screen.
After the song plays through once, it continues to play in the background as Flonne now awakens to it, wondering who would be singing so late at night. When she sees prinnies leaving, she is told by Big Sis Prinny to let them go, that they were finally able to atone for their sins.
The next morning, Laharl is angry when Etna tells him that several of the prinnies are missing. Laharl possibly wonders if maybe they left because they were mistreating them, to which Flonne gets slightly angry. Laharl wonders if Flonne knows something that she's not telling them, to which Flonne avoids the question.
Laharl then chooses to chase after the prinnies, "even if it is a big waste of time," and the story continues.
Flonne first explodes at Laharl for not showing more kindness and love, to which Laharl explodes back.
Later on, Etna reveals the story of Laharl's mother. A human witch who came to the netherworld to study, she was always talking about love and kindness, much like Flonne. However, the prince came down with a rare and deadly disease, and the only cure was the sacrifice of a loved one. It was after this that Laharl shut out the ideas of love and kindness. Finally coming upon the area where the prinnies are, Flonne, Etna, and Laharl all witness souls of the prinnies flying toward the red moon as they are reborn. Flonne comments that it is a heartwrenching sight, but Laharl screams at Etna to pull the souls back. The group encounters a Shadow leading the prinnies to the red moon, with Laharl demanding that it give all the prinnies back. After the fight, the Shadow asks Laharl why he is interfering with the Shadow's work. The Big Sis Prinny then shows herself, explaining to Laharl that this is Death's work, that he is leading the souls of the prinnies to the red moon to be reborn, and that if the prince truly loves his vassals, he will let them go.
After a second of contemplation, Laharl decides to let the souls go. Big Sis Prinny is so thankful for it, and now knows that she can leave in peace.
As Big Sis Prinny closes towards the Red Moon, Flonne asks her what sin the Big Sis Prinny committed. To which Big Sis Prinny responds that she took her own life, and that is a terrible and grave sin.
When Flonne asks why the Big Sis Prinny would take her own life, Big Sis Prinny responds...
"To save my son's life."
Big Sis Prinny goes on to explain that because of her death, her son shut out his feelings, but now they are slowly coming out again because of all the wonderful friends he has.
As Big Sis Prinny begins to leave, she asks Flonne and Etna to take care of Laharl, her old human body flashes for just a second before it turns to a white orb, and floats up towards the red moon, along with two other prinnies and the Shadow. This brief image reveals Big Sis Prinny to be Laharl's mother. The rest of the story is Flonne narrating about how sad this story of a mother and her son is, with Laharl finally calling Flonne by her name for the first time.
The song Red Moon plays once more while the prinny souls continue to float up to the Red Moon.