Young Blood, Old Souls

Luz Noceda prepares herself to rescue Eda, with King joining her. King explains how magic was once wild, until a mysterious witch named Belos arrived, claiming that he could "speak to the island". Belos established the coven system, resulting in him becoming the most powerful witch, and eventually becoming Emperor of the Boiling Isles. Under Belos' rule, witches who do not choose a coven are punished with petrification. Lilith brings her sister, Eda, to Belos in hopes that he will remove her curse. He instead orders Eda to be petrified, and orders Lilith to destroy Eda's palisman, Owlbert.

Luz and King purposefully get caught committing a crime to get into the Conformatorium, where Eda is being held. Luz finds Eda and manages to speak to her in her monster form. Eda tells Luz that Belos wants the portal to the human world, and that she needs to return home and destroy it. As Eda is taken away, Luz fights with Lilith, and they both pass through the portal to the human world. Lilith admits that cursing Eda was a mistake (she thought the curse would only last a day), as she wanted to get into the Emperor's Coven, but that Eda was willing to give it up for her. After returning Owlbert to Luz unharmed as a sign of trust, they return to the Boiling Isles together to rescue Eda.

Lilith plans to stay in the Emperor's Coven in order to spy on Belos, but she and King are captured, leaving Luz to confront Belos alone. Meanwhile, Willow and Gus rally the people in cheering for Eda's release. Luz, overpowered by Belos, is given the choice of giving up the portal to the human world (Belos claiming he has no intentions of world domination, instead wanting it for another propose), or have Eda suffer. Luz gives up the portal, but burns it upon leaving. Luz manages to rescue Eda, King, and Lilith, while Belos informs the citizens that Eda will be spared. After escaping, Lilith uses her magic to share Eda's curse, resulting in Eda returning to normal, but both her and Lilith's magic being weakened.

Later, Luz makes a video message for her mother, promising that she will find a way back home. Meanwhile, Belos sends a masked figure to spy on the residents of the Owl House, and uses the remains of the portal to construct another one.

"Young Blood, Old Souls" was first released on DisneyNow and video on demand on August 29, 2020 and first aired later that same day on Disney Channel.[7]

The A.V. Club's Kevin Johnson gave the episode a "B", stating the episode was an "enjoyable, tense, and intriguing finale" which also "inadvertently exposes the overall flaws" of the show. One such flaw Johnson felt was highlighted in this episode was the show's consistency with its depiction of magic, contrasting it to shows like Steven Universe and Gravity Falls which "really put in the work to make details cohere so that the overall world and premise stand out" while "The Owl House just feels shaky and broad". He did however praise the animation and art direction, stating that "the episode (and the show as a whole) really can bring some visceral power within the frame".[9] Bubbleblabber's David Kaldor gave the episode a "5/10", stating that "aside from competently serving that purpose as a finale" he didn't have "many positive things to say about it".[6]