Bloodlines and Birthright: A Novel from the World of Glass and Steele. The Uncensored Memoirs of a Book Hunter, #2

Lovers and loyalties are tested when scandals come to light. Memoirist Professor Gavin Nash and his friend Oscar Barratt travel to the picturesque shores of Italy's Lake Como in search of a rare book said to contain the spell for a magical tattoo. It's been hidden for centuries in the scriptorium of an ancient abbey, so it's dreadfully bad luck that they arrive just after it was given away. Worse still, their rivals turn up in the same idyllic village.
Perhaps luck has nothing to do with it. The book's new owner has no intention of parting with it easily. In exchange, he demands they recover a magic spell stolen by the local artless boatbuilder. But when Gavin and Oscar search the boatshed, the only thing they find is a dead body and signs of magic. With the mysterious Miss Wheeler following them on orders from her ruthless employer, the trio becomes entangled in a deadly web of murder, espionage, and long-buried secrets that others will stop at nothing to protect.