Sana Gupta has waited years to return to her ancestral home in Paris, with its labyrinthine halls and overgrown gardens. Sent away as a child when her mother disappeared, Sana has long puzzled over whether her mother's departure was just another of her famously unsolvable riddles. Now eighteen and ready to claim her inheritance, Sana arrives at the dark and dilapidated estate to find three strangers awaiting her: Fox, an eccentric prodigy who models himself after Sherlock Holmes; Isabelle, a seemingly innocent girl who shares an icy history with Sana; and Minho, a handsome young genius always wearing half a smirk. Per her mother's will, they've each received a cryptic invitation to compete in a contest of riddles for the deed to Razorthorn Manor—and the rumored treasure hidden within: a flower created by the gods themselves, able to grant any wish.

Feeling betrayed by her mother, Sana sets out to uncover the truth of where her mother really went, what links the competitors together, and what secrets the crumbling and disquieting house conceals. But her task won't be easy—for her competitors will do anything to win this twisted game . . . Set in a darkly shimmering Edwardian Paris where worship of the Roman gods never ended, A Riddle of Thorns drips with Gothic atmosphere, sizzles with romantic tension, and confounds with intricate puzzles and mysteries.