The era of the Crusades, sophisticated political intrigues and a brutal war for faith. Duke Louis of Bavaria is killed in front of numerous witnesses. The trail of this crime leads to the militant order of the Templars. However, members of the order are not guilty of murder... The Templars entrust the investigation to the young knight Orlando - the only one who suspects where the true criminals should be looked for. To establish the truth, Orlando, risking his own life, must penetrate the mysterious fortress of the Assassins - fanatical killers, whose leader is the mysterious Old Man of the Mountain, according to rumors, capable of opening the gates of the Garden of Eden to living people...