Dr. Kathryn Railly is a fictional character from the television series 12 Monkeys. She is portrayed by actress Amanda Schull and serves as a key figure in the narrative. Dr. Railly is a brilliant scientist specializing in virology, and her work becomes crucial in the fight against a deadly virus that threatens humanity. Throughout the series, Dr. Railly grapples with complex moral dilemmas and the implications of time travel. Her character evolves as she navigates relationships with other main characters, including James Cole, who is sent back in time to prevent the outbreak. Dr. Railly's intelligence and determination make her an essential part of the story.