As guardian of Lake Nostos, the Siren keeps the waters untouched by outsiders. Legend has it the waters of Lake Nostos have the capability to restore something to its former glory. Many men have tried to enter and take the water, but none have ever returned home. The Siren leads astray those who come to the lake with her seductive and enticing nature. By sprinkling some of the lake water on herself, she has the ability to morph into the object of the person's deepest desire. After engaging the person with the illusion, the Siren tempts the individual into stepping deeper into the lake where she eventually drowns her victim.
Prince Charming hears of the lake water's power from his ex-fiancée, Abigail, who mourns the statuesque state of her true love, Frederick. Though she knows it could possibly restore Frederick to life, no one has ever lived to succeed in retrieving the water due to a beast protecting the lake. Prince Charming insists he try, and heads there alone. As he approaches the lake to scoop up some water, the Siren senses a presence and bubbles up from below the lake's surface to welcome him. She tries to draw Prince Charming in with her alluring voice and walks closer to get a better look at him. He guards himself well, but is no match for her illusion trick. He watches in astonishment as the Siren literally becomes the person he loves the most, Snow White.
Prince Charming is powerless and gives in when the Siren kisses him while wearing the mask of Snow White's face, body and voice. She promises he can have everything with her, but Prince Charming declares he wants reality or nothing. Coaxing him in with a profession of love and another kiss, he pushes her away with the realization this isn't true love. Sneering, the Siren is somewhat impressed he is the first to look past her facade and forces him underwater. Attempting to swim back up, Prince Charming is trapped by a clump of seaweed wrapping around his ankle. He notices a lone dagger lying at the bottom seabed and hides it in his hand as the Siren glides by to force a kiss on him. Then, he stabs and kills the Siren for good. As she bleeds into the water, her disguise comes off and she reverts to her true form in death. ("What Happened to Frederick")
When Prince Charming returns to Lake Nostos in order to heal his mother after she is shot by a stray arrow, he discovers the lake-bed has dried up due to the Siren's prior death. As he and Lancelot search for any remaining water, they find the creature's skeleton. ("Lady of the Lake")
- Lake Nostos' origin is explained in the novel Red's Untold Tale where it is revealed that a fair washerwoman with blonde hair and a beautiful singing voice was cursed by a jealous queen and forced to live underwater in a spring, which the washerwoman later modified into a lake. According to the author's writer Wendy Toliver, the washerwoman is likely to be the siren seen onscreen, but if not, at the very least should be considered a descendant of the washerwoman.
|Once Upon a Time: Season One|
|"Pilot":||"The Thing You Love Most":||"Snow Falls":||"The Price of Gold":||"That Still Small Voice":||"The Shepherd":||"The Heart Is a Lonely Hunter":||"Desperate Souls":||"True North":||"7:15 A.M.":||"Fruit of the Poisonous Tree":|
|"Skin Deep":||"What Happened to Frederick":||"Dreamy":||"Red-Handed":||"Heart of Darkness":||"Hat Trick":||"The Stable Boy":||"The Return":||"The Stranger":||"An Apple Red as Blood":||"A Land Without Magic":|
|Once Upon a Time: Season Two|
|"Broken":||"We Are Both":||"Lady of the Lake":||"The Crocodile":||"The Doctor":||"Tallahassee":||"Child of the Moon":||"Into the Deep":||"Queen of Hearts":||"The Cricket Game":||"The Outsider":|
|"In the Name of the Brother":||"Tiny":||"Manhattan":||"The Queen Is Dead":||"The Miller's Daughter":||"Welcome to Storybrooke":||"Selfless, Brave and True":||"Lacey":||"The Evil Queen":||"Second Star to the Right":||"And Straight On 'Til Morning":|
|Once Upon a Time: Specials|
|"Magic is Coming":||"The Price of Magic":||"Journey to Neverland":||"Wicked is Coming":||"Storybrooke Has Frozen Over":|
|"Secrets of Storybrooke":||"Dark Swan Rises":||"Evil Reigns Once More":||"The Final Battle Begins":|
Note: "Archive" denotes archive footage.