London 1918 Fiona Figg finds herself back in Old Blighty saddled with shuffling papers for the war office. Then a mysterious card arrives inviting her to a fancy house party at Mentmore Castle. This year's Ascot-themed do will play host to a stable of animal defense advocates and Fiona is tasked with infiltrating the activists and uncovering possible anti-war activity. Disguised as the Lady Tabitha Kenworthy Fiona is more than ready for the 'mane' event but the odds are against her when both her arch nemesis dark-horse Fredrick Fredricks and would-be fiance Lieutenant Archie Somersby arrive unexpectedly and 'stirrup' her plans. And when a horse doctor thuds to the floor in the next guest room Fiona finds herself investigating a mysterious poisoning with some very hairy clues. Can Fiona overcome the hurdles and solve both cases or will she be pipped to the post and put out to pasture by the killer?