Cassandra Railly is a fictional character from the television series 12 Monkeys, which is based on the 1995 film of the same name. She is a brilliant virologist who becomes central to the story's plot involving time travel and a deadly virus that threatens humanity. Cassandra is portrayed as resourceful and determined, often facing moral dilemmas as she navigates the complexities of her role in the fight against the impending apocalypse. Throughout the series, Cassandra's character develops as she interacts with other key figures, including James Cole, a time traveler sent to prevent the outbreak. Her expertise in virology and her strong will make her a vital player in the efforts to save the world, showcasing her resilience in the face of overwhelming challenges.