1Q84 by Haruki Murakami

In 1984 Tokyo, an assassin named Aomame and a ghostwriter named Tengo independently slip into a "parallel reality" marked by two moons and a malevolent cult.

This book contains: alcohol, alternate gender/sexual ideologies, animal cruelty and death, child abuse and parental neglect, controversial commentary, cult and institutional abuse, dark, disturbing, and aberrant themes, explicit sexual content (graphic, patently offensive, prurient, and pervasive), misogyny, sexism, and sexual objectification, murder, assassination, and sexualized death, psychological trauma, anxiety, depression, and suicidal ideation, sexual content involving minors (sexual exploitation, molestation, pedophilia), sexual violence and coercion (including BDSM elements linked to harm), stalking, supernatural / metaphysical elements tied to cult ideology and toxic relationships.