The Marten and the Scorpion

Darya scrapes a living as a pickpocket on the streets of Samarkand, a diverse metropolis at the centre of the Silk Road. If she wants to keep scraping a living, she'll have to pass her gang’s initiation: a death-defying climb across the city’s rooftops. But she’s so exhausted and malnourished that it seems impossible, and her time is running out.
When a forbidding swordswoman arrives in Samarkand from the East, and hires the gang to search for a mysterious box, Darya sees her chance. She has stumbled on two more recent arrivals, young caravan guards who are also interested in the box and whatever’s inside. They’re as formidable in combat as the swordswoman…and they can fly, leaping from building to building better than any pickpocket.
Darya makes them an offer: If they teach her their skill enough for her to pass her gang’s test, she’ll help them find the box first. Meanwhile, more factions are drawn into the hunt, including a rival street gang, a sadistic ex-Crusader, and the dreaded Nizari Assassins. And each of Darya’s allies has a separate, secret agenda. What’s inside this coveted box, who will end up possessing it, and to what use will it be put?