Inspector Tibbett joins his wife Emmy for the twentieth reunion of her Royal Air Force squad. It's a bittersweet trip for Emmy: she loved her work with the RAF, and she was in love with one of the pilots, but their happiness ended abruptly when he killed himself, crashing his plane into the North Sea. At the reunion, Emmy is surprised to realise that she may have been the last person to see her former sweetheart alive. And she's more than startled to discover that virtually everyone connected with that fatal flight had something to hide...