In this urban fantasy novel, the third installment of a series, the protagonist, a young Shadowhunter, travels to the titular city, a place of great significance to the secretive world of demon hunters, warlocks, vampires, and other supernatural beings. She is on a quest to find a cure for her poisoned mother, but her mission quickly becomes entangled with a larger conflict as she uncovers dark secrets about her family's past and the true nature of the Shadowhunters. As the city becomes a battleground, alliances are tested, and the protagonist must confront a powerful enemy who threatens to destroy everything she holds dear, all while grappling with her evolving feelings for her enigmatic companion.

The book follows the story of a young woman in 18th-century France who, desperate to escape an arranged marriage and yearning for freedom, makes a Faustian bargain with a mysterious god-like figure to live forever without being remembered by anyone she meets. Her immortality becomes a curse as she moves through the centuries, leaving no mark on the world until, 300 years later, she stumbles upon a young man in a bookstore who, to her shock, remembers her name. This encounter unfolds into a tale of love, memory, and the intrinsic value of leaving one's mark on the world.

This novel is a satirical romance set in a dystopian near-future where America is on the brink of financial collapse, youth obsession rules, and love is the only salvation. The story revolves around a middle-aged, neurotic man who falls in love with a much younger woman in a society where digital communication is the norm, and privacy is a thing of the past. Their relationship unfolds amidst a backdrop of economic and social chaos, providing a poignant commentary on modern life.