Legal clerk Jim Steele VC is horrified when told by Eunice Weldon, the girl he loves, that she has taken the post of secretary to the mother of Digby Groat and is going to live in the Groat family home in Grosvenor Square.
As well Jim might, for Digby Groat out Sir-Jaspers Sir Jasper. Among other things, he is not above menacing his kleptomaniac mother and torturing small animals. His mother will inherit a fortune from her deceased brother on a certain date if her niece Dorothy Danton cannot be found. Since Dorothy disappeared in a boating accident while still a baby and has not been seen since, it looks as if the Groats will soon be extremely wealthy. But Jim, who is interested in the Danton case, is determined they will never get their hands on the fortune.
The first night under the Groats' roof Eunice receives an unseen nocturnal visitor who leaves a card stamped with a blue hand, advising her to flee the house. Despite this ominous warning, after Jane Groat suffers a stroke Eunice stays on. Other blue hand marks appear at the house and soon the reader is in the thick of a plot featuring a mysterious veiled woman, drugs, gangs, derring-do on trains, in planes, and on the high seas, and a lot more besides. Aside: if this had been a film, no doubt the audience would cheer when they see how a minor baddie comes to a particularly spectacular end.
The plot is revealed fairly early in the book, and the last part taken up by a prolonged chase involving cars, vans, yachts, and seaplanes. Jim and Eunice are standard models of rectitude, and it is the cunning solicitor Septimus Salter and the Portuguese yacht captain who are the most interesting characters. A fairly routine book for Wallace, though fans will want to add it to their collection.
My verdict: There's somewhat less mystery in Blue Hand than in other Wallaces and parts of the plot are transparent, but still a few twists will catch the reader by surprise. The pace picks up towards the end of the book and it was refreshing to see a novel whose heroinne has backbone.