Based on true events, The Hunt For The Unicorn Killer tells the shocking story of Ira Einhorn, a respected American peace activist in 1970s America. He lives with Holly Maddux (Naomi Watts), but when he tries to leave him in 1977, she suddenly disappears under mysterious circumstances. Somewhat later, her lifeless body is found in a suitcase in the flat of Einhorn, who has meanwhile fled the country and in the following years cleverly manages to stay one step ahead of the authorities. However, Holly's father remains determined to bring justice in his daughter's name and after a lengthy manhunt, he finds the 'unicorn killer' in France in 1997..