Overflow follows a group of twenty-somethings as they find themselves, explore their connections to the magic that surrounds their town and strengthen their relationships with each other. Brought together by a book of Prophecies and the looming possibility of the apocalypse, they must decide whether it is worth it to save the world, or to simply save themselves.

Isaac, a charismatic and lonely man who acts as the backbone of his group of friends, the Hell Club, is given a Prophecy of falling in love. Iris, a powerful witch, pushes herself to her limits fighting the force that stole her mother from her. Park, new to town and unmoored from the comforts of life in a big city, is nearly martyred. Eve is plagued by nightmares and her partner Derek is convinced that a particularly nasty Prophecy means he'll die, leaving Eve to face the world on her own. C, Park's teenage sister, is wrestling with her identity and her place in the world, feeling as though she's meant for greater things than her new small town offers her.

Faced with their own fears, attachments to each other, and ideas about the future, the Hell Club must overcome the hurdles thrown at them and think of the greater good.