A pair of young men living in the 21st century relive the tales of one of their ancient forbearers in this historical drama. Kamran (Adam Echahly) is a 12-year-old boy of Iranian heritage whose older brother, Nader (Puya Behinaein), is slowly dying. Kamran and Nader's family puts a great value on preserving the oral history of their ancestors, and Nader is passing on this responsibility by telling his brother the story of their distant relative, the great scientist and poet Omar Khayyam (Bruno Lastra). In the 11th century, Omar is close friends with Hassan Sabbeh (Christopher Simpson), a passionate Muslim warrior, and they are both infatuated with the lovely Darya (Marie Espinosa). However, in time Omar and Hassan's paths in life diverge; Omar joins the court of the Sultan Malikshah (Moritz Bleibtreu) and uses his considerable wisdom to study mathematics and the stars, while Hassan succumbs to his rage and forms a cult of killers known as the Assassins. The Keeper: The Legend of Omar Khayyam was the first feature film for Iranian-American director Kayvan Mashayekh.