Charlie is a 32-year-old former anthropology student and artificial intelligence enthusiast. Unemployed, he spends his days attempting to make an income through small stock market investments. He views his life in a state of emotional neutrality until he acquires his new android and begins pursuing his upstairs neighbor.

Miranda is a 22-year-old university student living in the apartment above Charlie. She is physically alluring and initially reluctant to share her emotional life. She studies how ideological contexts influence history and carries a heavy burden of guilt concerning a high school friend.

Adam is one of the first 25 models of highly advanced artificial humans available on the consumer market. Built as an intellectual and conversational companion, he possesses a foundational personality programmed jointly by Charlie and Miranda. He processes information through vast internet searches and quickly develops a keen interest in theoretical physics, poetry, and objective morality.

Mark is a young boy whose parents seek to abandon him to the care of strangers. He represents the natural progression of human childhood, learning through play and experience rather than programmed code.

In this alternative 1980s timeline, Turing is a living, celebrated scientist who survived World War II to advance robotics and technology. He acts as a leading authority on artificial consciousness and actively tracks the development of the 25 consumer-grade androids.

Gorringe is a man involved in a complex legal situation with Miranda. He is scheduled to be released from prison soon, a fact that causes Miranda immense distress and dictates her cautious behavior.

Maxfield is Miranda's father and an author of moderate success living in Salisbury. He suffers from autoimmune illnesses and prefers working without modern technology, choosing to write his manuscripts entirely by hand.

Mariam was Miranda's closest childhood friend during their last year of high school. She suffered a traumatic experience that deeply affected Miranda's life trajectory and ongoing choices.

Thomas is Alan Turing's romantic partner, accompanying the famous scientist during his public outings in London.

Demis is a scientist and colleague of Alan Turing who assisted in developing a sophisticated program capable of mastering the intuitive board game Go.