First published in 1891, the novel begins with the death of its main character, a mad philosopher known for spreading pessimistic theories about "humanity." Borba leaves his fortune—including his dog of the same name "Concas Borba"—to Rubião, his devoted companion and teacher. Granted with wealth beyond his dreams, Rubião soon indulges in a life of luxury, provided he continues to care for the dog Concas Borba with the same dedication he showed to humans. Lost in the bustling and troubled world of Rio de Janeiro in the late 1860s, it wasn't long before Rubião became a target for the city's flatterers, who could easily spot his naivety.