Departing from classic Greek mythology, these Siren sisters are the offspring of a contentious relationship between Amphitrite, Goddess of the Sea, and Hades, ruler of the Underworld (also known as The Below). During a fierce battle Amphitrite drains Hades of his power and banishes him to The Below for eternity. Not one to remain forgotten, Hades maintains a presence on Earth in the form of a renegade AI-generated animation broadcasting live over YouTube.
Hades exacts his revenge on Amphitrite by kidnapping her daughters, Evan and Evaline, and puts them to work capturing souls for him. Evan uses her song to lure Gabe, a musician, but ends up falling in love with him instead. Evan and Gabe start a band and a relationship together. Evan's jealous sister, Evaline, steals Gabe and takes him to The Below. She also takes Evan's human memories, leaving Evan to wander the world above in a state of confusion.
Evan encounters Pirate Davey and Malador in her travels. The two former sailors are living rough after losing everything they had while pursuing the Siren's song. One night Pirate Davey hears Evaline's song from beyond the camp and the three unlikely companions follow it into a portal which leads them to the world below.
Gabe remains trapped in The Below, enchanted by Evaline's magical and erotic spell, and unable to access his human memories. Gabe encounters Bennu, a Bird Man, who tells Gabe that if he stays with Evaline, he too will lose his humanity. Soon after, Gabe begins to change.
Evaline has hidden the memories in a magical tree, where Evan and Gabe reunite, as Gabe struggles to retain his human traits. Together they view their stolen memories, reclaiming the memory of their love before a final battle ensues between Evan and Evaline. With help from the audience and the other characters, this stand off determines who will control the future.