In a world shaken by an epidemic of madness that spreads through language and speech, a former linguist Murat Siyavus who has been at a long lasting hideout, is the only person mysteriously unaffected by this disease. Hunted by the ruthless Anti-Epidemic Institution, Murat is forced to leave the safe zone and flee within the flames and ruins of the mysterious streets of Istanbul, where he searches for the secret of his "hot skull" - a lasting mark of the disease.