Gotham's Children of Shadow

Seven months after the end of the Second Giant War, Desdemona Sinclair, the daughter of Hades, is bored. A Gothamite at her heart, raised by a single drug addict mother in the Narrows, she craves the chaos of something always happening.
But with Camp Half-Blood practically empty, she is restless. She decides to return to her home city, under the claim that there must be other demigods living there, not knowing who or what they are. She drags her half-brother, Nico Di Angelo along for the ride, partly at Chiron's insistence.
With the help of Rachel Dare and Rachel's father's bank account, Desdemona and Nico are enrolled at Gotham Academy and have a small apartment on the outskirts of Crime Alley. At the insistence of Leo Valdez and Calypso, Desdemona becomes a vigilante.