Teddy is a young, intelligent boy traveling on an ocean liner with his family. He presents a contrast between his disheveled, childlike appearance and his adult intellectualism. Claiming to be a reincarnated Indian man seeking spiritual enlightenment, he documents his thoughts in a journal and casually discusses theology and mortality. He rejects Western logic and materialism, preferring a detached, unsentimental approach to the world around him.

Bob is a professor at Trinity College and a passenger on the ocean liner. As a colleague of the Leidekker Examining Group that previously studied Teddy, he represents the academic establishment and conventional logic. Dressed in clothes typical of elite university seminars, he approaches Teddy with a mix of curiosity and growing frustration. He struggles to comprehend a worldview that actively rejects formal education and logical reasoning.

Mr. McArdle is a radio voice actor who projects a stereotypically masculine and authoritative persona. Despite his deep, commanding voice, he lacks genuine control over his family dynamic. He places high value on material possessions, prioritizing items like his Gladstone suitcase and Leica camera. His behavior is heavily influenced by his past experiences in the military, resulting in a tense and abrasive demeanor.

Mrs. McArdle is a passenger on the ocean liner, traveling back to America with her family. She appears largely disengaged from her children, interacting with them in a sleepy, distant manner. Her primary interactions involve trading morbid, sarcastic threats with her husband.

Booper is Teddy's younger sister, characterized by a jarring blend of childishness and verbal cruelty. She casually discusses morbid topics, such as feeding parents poisoned marshmallows. She mimics the dark humor she hears from her parents. She harbors a strong dislike for nearly everyone on the ocean liner and rejects her brother's intellectualism.

Myron is a young passenger on the ocean liner who recently lost his father in the Korean War. He endures relentless bullying from Booper, who mocks him for not understanding the definition of an orphan.