Rhys Bowen’s Royal Spyness series, starring fictional royal Georgiana Rannoch solving crime in 1930s England, has offered rollicking good fun throughout its run. The latest volume, ON HER MAJESTY’S FRIGHTFULLY SECRET SERVICE, is an inconsistent entry in the series that doesn’t offer particularly titillating or intriguing mysteries or surprises.

"It’s down to the charm of [Bowen's] characters that readers will want to see Georgie through to the end."

After the events of CROWNED AND DANGEROUS, Georgie and her fiancé, Darcy O’Mara, are happily engaged. But Darcy, who works for British intelligence, is soon off on another undercover mission, and Georgie is left to her own devices. Thankfully, she soon receives a letter from a school chum in need of companionship in Italy. Coincidentally, Georgie is summoned to Buckingham Palace by Queen Mary, who’s worried, once again, about her wayward son, the Prince of Wales, and his beau, Wallis Simpson. She tasks Georgie with keeping an eye on her royal cousin, who just so happens will also be in Italy, on her journey abroad.

This premise --- Georgie being given an assignment by the queen, only to run into all of her friends and family in an impractical coincidence --- is one that Bowen has employed to great effect before. But it wears thin by this, the 11th volume in the series. Bowen has built up sufficiently engaging characters that she shouldn’t need to rely on such predictable gimmicks, which hamper the development of a convincing mystery.

As a result, ON HER MAJESTY’S FRIGHTFULLY SECRET SERVICE comes across as an uninspired retread of territory Bowen has stomped over before. It’s down to the charm of her characters that readers will want to see Georgie through to the end.