By the Pricking of My Thumbs by Agatha Christie
Tommy and Tuppence are well into middle age here, but still have a wonderful relationship. Tommy’s crotchety old aunt dies, but before she does Tuppence meets another woman at the same nursing home who says a few mysterious things that unnerve her. When the lady goes missing, Tuppence sets off to find her, ostensibly to return a painting.
The mystery is a bit convoluted but enjoyable and wraps everything up in the end well. I love that Tuppence is still willing to go on an adventure and that Tommy supports her. I may have to give in soon and get BritBox so I can watch the new Agatha Christie's Tommy & Tuppence series....