In 24 hours, PI Adrian Montana arrives in Italy, inherits a bookshop, an apartment, and a mischievous marmalade Cheshire cat, learns his aunt was murdered, discovers his aunt's lawyer's body in the basement of the bookshop, witnesses the assassination of a Cardinal, falls in love with a priest, and becomes the target of a ruthless human trafficking kingpin with ties to the Vatican.

As Adrian dives deeper into the mystery of his aunt's death, his path crosses with Luca, a reserved yet magnetic priest who insists on keeping their relationship strictly professional. But as danger closes in, Adrian finds it increasingly difficult to ignore his growing feelings. With the pieces of the puzzle leading him ever closer to the truth—and into the killer's sights—Adrian must balance unraveling the conspiracy with his feelings for the priest.