[DeepL Translation - needs review] Chihaya, a doctor, dissects a corpse in accordance with her father's will, and finds a code on the stomach lining. Chihaya learns that her father quit the police force 28 years ago to pursue a serial killer, and she tries to decipher the code carved in his stomach. At the same time, a murder case very similar to the one that occurred 28 years ago occurs. Chihaya and Shiori, a pair of doctors, unravel a mystery that is intertwined in the present and the past...
From a language learning perspective - there are a scattering of idioms throughout the book, but there's aren't many flourishes to the writing and it's otherwise fairly standard and leaning towards dialogue heavy. Some medical and criminal vocab, but minimal and the few very technical terms are explained by the characters themselves.
I think if you can handle a general adult novel and don't mind looking up a handful of words this will pose no issues.
From the 'did I enjoy this' perspective...m