In the supernatural city of Arcadia, Leila Starquin has lived an ordinary live despite being surrounded by extraordinary Mystic beings. Living a carefree life, content with her studies and steady routine as one of the few humans left in the city, Leila's world flips upside down when she stumbles upon a crime scene on the night of her birthday. She has somehow become the central suspect in a series of mysterious disappearances of Souls, where the Soul Eater is ripping away peoples souls before they can properly pass onto the afterlife. Determine to prove her innocence, she reluctantly teams up with Grim, who is secretly the shepherd of souls and spirits or Grim Reaper. He is the detective on the case and at first suspects Leila involvement in the crimes but when her fate becomes intertwined with his own, he has no choice but to protect her instead. Hearts are on the line and loyalties are tested and the very reason could shatter. Can one human girl be the key to saving the afterlife?