Lord Apollo & the Colleen — Suzanne G. Rogers

Five years after Theo King's supposed death, he has returned to Graceling Hall, but a mystery remains. A stranger is buried in his grave, and nobody knows if the man's death was accidental…or murder. As Theo resumes his former life, the dead man's sister shows up on his doorstep to hold him accountable. If he helps this Irish spitfire solve the mystery, will she finally leave him in peace?