When Oskar, a sensitive, bullied 12 year old boy living with his mother in suburban Sweden, meets his new neighbour, the mysterious and moody non-binary Eli, they strike up a friendship. Initially reserved with each other, Oskar and Eli slowly form a close bond, but it soon becomes apparent that there is more to Eli than could ever be expected. Eventually, Eli shares their dark, macabre secret with Oskar and their connection to a string of bloody local murders. Is Eli a girl? Is Eli a boy? Are they even human?