Human Stain is the third thriller in the Gravitas series. Gravitas is a security and investigative business established by Stewie Stewart. True to his promise he only employs ex military veterans. In this thriller he is approached by Sam 'Topaz' Alleyne for help.By day Sam hauls heavy carcasses at the meat market; at night he's a DJ in an upmarket club, his escape from a past life where killing was a legitimised trade. His sister Gracie is a nursing volunteer in a country torn apart by persecution and civil war. Daily she deals with refugees abandoned by a Government that doesn't care. But, despite the sickness and abuse she witnesses in the refugee camp, Gracie doesn't know what real horror means. When Sam discovers Gracie has disappeared, he sets out to find her. But even an enraged bull knows when it cannot succeed alone. In desperation he approaches his friends at Gravitas for help. But none of them is prepared for the deep-rooted evil they are about to uncover.