Un-Go - Season 1 Episode 6 The Code Too Simple

Shinjuurou is approached by Yajima, an old friend of Rinroku, who found a piece of manuscript in a book given to him by an inmate whilst he was in prison. After discovering Yajima's wife Takiko's fingerprints on the paper, Shinjuurou informs Rie, who investigates how the book relates to Rinroku. Shinjuurou later hears from Yajima about how his children disappeared and his wife went blind, allegedly having an affair with Rinroku. Shinjuurou looks at all the books Rinroku bought from the Yajima family, finding more hidden codes which are revealed to be from Yajima's children. As it turns out, Rinroku had helped the children and placed them in child care to avoid Takiko's neglect, and they are soon reunited with Yajima. Afterwards, Shinjuurou confronts the prisoner who gave Yajima the book, learning something shocking.