When Jacob Wheeler embarks on a Mediterranean cruise aboard the SS Canberra, he dreads spending sixteen days with his overbearing granny and his annoying cousin Millie while his grandpa, a world-famous detective, investigates a high-profile cheese theft in Italy.

But when Jacob discovers a suspicious cellphone on a display table of cheese aboard the cruise, he realizes he just might be able to help his grandpa solve his case after all.

Convinced the cellphone belongs to a criminal, Jacob is determined to link suspicious characters aboard the SS Canberra to the mysterious crates being smuggled onto the ship. Certain there's a connection to the Parmigiano Reggiano cheese heists in northern Italy, Millie and Jacob hunt for clues aboard the cruise while avoiding the wrath of Granny and exploring various Mediterranean ports.

But when the hunt heats up, Jacob wonders if they've taken the case too far.

Will he be able to collect enough evidence to help his grandpa? More importantly, will he be able to catch the thieves before the thieves catch him?