The first time she ran away to Paris, she was eight years old. Young enough to think she could escape for good. She’d found her way to the Arènes de Lutèce, the remains of a Roman amphitheater from the first century AD. It was, perhaps, the city’s oldest blood-soaked ruin. Two thousand years before, gladiators had warred to the death before a cheering, bloodthirsty crowd, until the arena—and its crowd—were overtaken by an equally bloodthirsty barbarian horde. For a time, it had been a cemetery; now it was a tourist trap, yet another heap of stones for bored schoolchildren to ignore. By day, at least. Under the midnight moon, it came alive with Downworlders, a bacchanalia of faerie fruits and wines, gargoyles enchanted by warlock magic, waltzing werewolves, vampires in berets painting portraits in blood, an ifrit accordionist who could make you weep yourself to death. It was the Paris Shadow Market, and from the moment Céline first saw it, she felt herself finally home.

That first trip, she’d spent two nights there, haunting the booths, befriending a shy werewolf cub, sating her gnawing hunger with the Nutella crepe that a Silent Brother had purchased for her, no questions asked. She’d napped beneath the tablecloth of a vampire’s jewelry stand; she’d whirled with horned children in an improvised faerie revel; she’d finally discovered what it meant to be happy. On the third night, the Shadowhunters of the Paris Institute tracked her down and returned her home.

That was when she learned—not for the last time—the consequences of running away.

We love you too much to lose you.

That night, Céline had curled fetal in the corner of the basement, back still bloody, and thought, So this is how it feels to be loved too much.

Their mission was straightforward. First, track down the warlock Dominique du Froid’s booth at the Paris Shadow Market. Second, find some evidence of her shady business dealings with two rogue Shadowhunters.

“I have reason to believe they’ve been trading Downworlder blood and parts to her in return for illegal services,” Valentine had told them. He needed proof. It was up to Céline, Stephen, and Robert to find some.

“Quietly,” Valentine had cautioned. “I don’t want her tipping off her associates.” Valentine made the word “associates” sound like a vulgarity. For him, it was: Downworlders were bad enough, but Shadowhunters allowing themselves to be corrupted by a Downworlder? That was unforgivable.

Step one proved simple. Dominique du Froid was easy to find. She’d conjured her name in neon lights, right out of thin air. Literally—the letters glowed brightly, three feet above her booth, with a neon arrow pointing down. DOMINIQUE DU FROID, LES SOLDES, TOUJOURS!

“Just like a warlock,” Robert said sourly. “Always for sale.”

“Always on sale,” Céline corrected, too quietly for him to hear.