Holly Gibney first appeared as a relatively minor but crucially important character in Stephen King’s 2014 mainstream thriller Mr Mercedes, in which the psychopathic Brady Hartsfield, the titular Mr Mercedes, goes on a bloody killing spree until stopped by a retired detective called Bill Hodges. Holly, who helps Bill crack the case, is introduced as a shy, unsure and troubled girl — blessed, however, with an eidetic (incredibly vivid) memory, extraordinary observational skills and genius-level computer expertise. While not stated, it is clear that Holly is on the spectrum.