First of all, the cover art is gorgeous. I love the quote from Dickens that inspired the title. Both the quote and the prologue drew me into the world and prepared me for elements of the otherworldly. I'm curious to find out who the boy is that young Lucie met that night.
James and his friends are interesting, especially the mystery surrounding his slipping into darkness. There seems to be a potential love triangle being built, so that should prove fascinating as well.
I have only previously read City of Bones, so it's nice to find this new series can also be a good entry point into the Shadowhunter universe.