I read this book in 2012-2014 when I was middle school. The cover was white or cream and covered in black and red curly connected illustrations o magic things like mannequins and a mask person wearing a top hat (these were really small illustrations) the back cover had the main character (the irish boy with i think red hair) illustrated. The book was in english and seemed pretty knew. it was maybe 1.5-2 in thick with a hard cover.Setting: somewhere in NYC probably BrooklynMain character is boy ( i think irish). He does magic tricks and meets a chinese girl named Jin who works as a pyrotechnic with her grandpa. The book begins introducing the antagonist who is not human and has boss called the Sandman or the Boneman or something not human. There are people who are "protectors" of the NYC boroughs and they are in danger. there is one part where the boy and jin go to save a girl who is the protector and they are chased through a house by the antagonist's allies. Jin and her grandpa have a firework cart and "cinnabar" is really important to them because it has healing/power properties. There are a few pictures in the book (maybe 10 in total) that are realistic and black-and-white. One was a close up of Jin with cinnabar red drawn on her forehead or somewhere on her head. another picture was of a fight scene between the antagonist and jin's grandpa who sacrifices himself. there was another picture of a Catherine wheel firework. it was when Jin and the MC are sitting somewhere and just watching it. The book in general is about trying to defeat the antagonist and save the NYC boroughs' protectors. The MC has a connection to Brooklyn b/c his dad helped build the bridge and it's implied that he died building it. LIGHT SPOILER AHEAD!!!!at the end they find the antagonist and it comes down to a card game between the MC and the antagonist. the cards are special cards and I think "devil's advocate" was a big deal. They were cards from whatever world the antagonist is from. MC figures out a trick to win the card game. the antagonist goes to report to his boss at the end and he gets turned to dust by the sandman/boneman ( i think). Jin and the MC are implied to get together.
A crossroads can be a place of great power.So begins this deliciously spine-tingling prequel to Kate Milford’s The Boneshaker, set in the colorful world of nineteenth-century Coney Island and New York City. Few crossroads compare to the one being formed by the Brooklyn Bridge and the East River, and as the bridge’s construction progresses, forces of unimaginable evil seek  A crossroads can be a place of great power.So begins this deliciously spine-tingling prequel to Kate Milford’s The Boneshaker, set in the colorful world of nineteenth-century Coney Island and New York City. Few crossroads compare to the one being formed by the Brooklyn Bridge and the East River, and as the bridge’s construction progresses, forces of unimaginable evil seek to bend that power to their advantage. Only two orphans with unusual skills stand in their way. Can the teenagers Sam, a card sharp, and Jin, a fireworks expert, stop them before it’s too late?A richly textured, slow-burning thriller about friendship, courage, love, and the age-old fight between good and evil. ...more