King Stefan and Queen Lia have two daughters whom they name Aurora and Luna. However, as time goes by, they eventually realize as Luna gets older that she is a werewolf. At first, they manage to contain her in the dungeons once a month during every full moon, but when Luna's wolf form becomes too strong for that, Stefan and Lia decide that they have no choice other than to get her away from the kingdom. Luna is sent to live with her grandmother Flora, who is Lia's mother, in a house deep in the forest. Years go by, and during that time, Flora has been making a red hooded cloak infused with strong magic that can repress Luna's transformations. When the cloak is complete, Luna is able to return to the kingdom, as long as she wears the red cloak every wolfstime.
Luna returns to the kingdom, reuniting with her parents. However, she discovers that Aurora has been placed under a sleeping curse by the witch Maleficent. In retaliation, Luna decides to unleash her wolf form onto Maleficent, and travels to Maleficent's fortress. However, when she comes face-to-face with Maleficent, the sorceress manages to manipulate Luna's emotions by bringing up how her parents sent her away just because she was different. Luna, although stubborn at first, is emotionally broken by Maleficent, who offers to teach her magic and help her get revenge on her parents. Eventually, Luna becomes immensely powerful under Maleficent's guidance. She goes to Flora's cottage in the woods and kills her, before magically disguising herself as Flora and sending a letter to the kingdom. Desperate to keep Luna's disappearance a secret, Stefan and Lia go to the forest with armed guards, although the guards are overpowered by Luna, who then slaughters her mother and father, before claiming the throne as her own and ruling over the kingdom with an iron fist. She creates an army of werewolf soldiers that she refers to as her "children", and plans to spread lycanthropy across the Enchanted Forest. However, the Dark Curse takes everyone - including Luna - to a land without magic.
In Storybrooke, she becomes Rose Flanagan, who works as a bartender at The Rabbit Hole. During one of her shifts, Rose meets Sheriff Graham, and when Rose gets off work they go back to Graham's apartment and hook up. The next day, Rose is approached by Mayor Regina Mills, who warns her to stay away from Graham. Rose realizes that Graham has some sort of relationship with Regina, but continues to sleep with Graham anyway. This infuriates Regina to the point where she orders Graham to break things off with Rose. Graham abruptly acts cold and hostile towards Rose, before telling her he doesn't want to see her again. Rose, suspicious that Regina has some sort of blackmail on Graham to make him do her bidding, breaks into the Mayor's office and goes through her drawers until she comes across a box with a glowing heart in it. Horrified, Rose meets with Graham while he is doing a talk at Storybrooke Elementary School, and tells him what she saw. Regina's son Henry overhears the conversation and later confronts Rose, explaining that everyone in Storybrooke comes from the Enchanted Forest where Regina is actually the Evil Queen, who rips out people's hearts in order to control their every move.
- Luna is based on Little Red Riding Hood and the Big Bad Wolf from the fairytale Little Red Riding Hood.
- Additionally, she is based on Moon from the fairytale Sun, Moon, and Talia.
- Luna means "moon" in multiple languages, referencing her lycanthropy.
- Her cursed surname "Flanagan" derives from the Gaelic "flann" meaning red.
- S1, E01: "Once Upon a Time"