Guardian Spirits by Jordan L. Hawk

Psychic medium Vincent Night and his lover Henry Strauss have spent months striving to uncover the dark secret harbored by Vincent’s dead mentor, James Dunne. Their only clue comes from a journal: Dunne was seeking to restore the Grand Harmonium, an artifact meant to breach the walls between life and death.

Fate seems to intervene when Henry and Vincent are offered a job investigating the haunted orphanage where Dunne lived as a youth. But the ghosts of the orphanage don’t rest easily, and the lovers soon find themselves in a battle to locate the Grand Harmonium before it falls into the wrong hands—and unleashes evil upon the world.