The Dark Artifices Trilogy by Cassandra Clare

It’s been five years since the events of City of Heavenly Fire that brought Shadowhunteres to the brink of oblivion. Emma Carstairs is no longer a child in mourning, but a young woman bent on discovering what killed her parents and avenging her losses. Together with her parabatai Julian Blackthorn, Emma must learn to trust her head and her heart as she investigates a demonic plot that stretches across Los Angeles, from the Sunset Strip to the enchanted sea that pounds the beaches of Santa Monica