A Sea Change by Cassandra Clare

Embark on a seafaring murder mystery from Greece to Constantinople with Matthew Fairchild, his loyal dog Oscar Wilde, and Sylvain Verlac, a captivating Parisian Shadowhunter.

Most travellers are running from—or searching for—something. But not Shadowhunter Matthew Fairchild and his loyal golden retriever, Oscar Wilde. No. Matthew is searching for himself aboard the Majestic, a grand 19th century ocean liner sailing from Greece to Constantinople.

Matthew wants nothing more than to mourn the death of a friend and peacefully enjoy his travels before reuniting with his friends James Herondale and Cordelia Carstairs at the London Institute of Shadowhunters—a secret society of angel-blooded humans who protect the mundane world from demons and Downworlders. But that’s interrupted when someone is murdered on the ship—and a vampire Downworlder lurks in the darkness.

Together with Sylvain Verlac, a mysterious and captivating Parisian Shadowhunter with a secret grief of his own, Matthew must find the murderer on the Majestic before death strikes again.