Summary: Albert Campion assists the Gyrth family in protecting a priceless chalice in the family for hundreds of years against an international theft ring focused on creating private collections of priceless treasures.

The male heir of a landed family, the Gyrths, is estranged from his father and wandering London’s streets when Campion finds him. Campion is on an urgent mission. For generations, the Gyrths have guarded a silver chalice. Their grant of the land depends on keeping the chalice secure. Campion has learned that an international group of thieves is seeking the chalice. This group has a peculiar set of rules by which they play. They steal for one another’s private art collections. And if the particular thief tasked with stealing a treasure is caught or dies, they cease their efforts in stealing that object.

Campion and the young man, Val Gyrth return to his father’s estate, close on his 25th birthday, when he is to engage in the ritual of the secret room. Meanwhile, his Aunt Di has been acting as the Keeper of the Chalice and has been showing it to a pack of guests. Then she turns up dead in a nearby forest, looking frightened out of her wits. Curiously, her body is laid out as if for burial, yet the death is ruled as due to a bad heart. Through Campion’s foresight, he protects the chalice that had been left unguarded in Aunt Di’s cottage.

Allingham creates a delightfully twisty plot involving a monster roaming the forest, an old witch and her mentally impaired son, a band of gypsies, a chase with Val’s sister Penny, Val and Campion trying to elude thieves seeking the chalice, a brash and rude woman who owns a nearby stable, and an American professor interested in the lore of the chalice, and his daughter Beth, who becomes Val’s romantic interest.

I won’t trace all those twists, but all these characters, and a few other minor ones as well as the faithful Lugg play a part leading up to a climactic scene at the secret room on Val’s 25th birthday. Campion’s eccentricities cover a shrewd schemer, yet as the climactic scene approaches, we find ourselves wondering if he has been too clever for his own good, and in fact he is saved only by help from an unexpected quarter. All in all, this was a delightful and diverting story, even though it pressed the limits of plausibility at points. ( )

Number 3 in the series. The character is developing better, somewhat enjoyable, but it doesn't really hold up to timeas well as other mysteries of that time period. ( )

May 2018 reread:
I am downgrading my rating of this from 4 to 3 stars. My previous rating was based upon fuzzy memory of reading this years before. I found on this reread that something about the blend of mystery & adventure doesn't quite work for me in this. I can't put my finger on what exactly the problem is as these are two genres I generally like both separately & together. ( )

My first Campion book. Will try more, though this one got draggy toward the end for me. Not sure whether it was the story, the writing or me.
But there were some good scenes and exchanges and descriptions:
"All right," said Mr. Lugg. ... "Whilst you're been messing about with The Motorist's Lunch," ... I'll go and get something to eat in the bar. It's mugs like you wot changes 'The Blue Boar' into 'Ye Olde Stuck Pigge for Dainty Teas.'"
"My dear young lady, there are lots of rum professors.There's nothing unusual about witchcraft. I used to be a bit of a wizard myself, and I once tried to change a particularly loathsome old gentleman into a seal on a voyage to Oslo. Certainly the vulgar creature fell overboard, and they only succeeded in hauling up a small walrus, but I was never sure whether I had done it or not."
"You'll be danger in a few years' time. I'll come and sit at the back of the church when you're married and weep violently among all the old maids." ( )

Quite the romp! I love the characters, the humor and the twists and turns. A fun mystery. Albert Campion is a favorite! We love Lugs too! Good narrator with excellent voices. ( )