Black Onyx - Sheoaks Equestrian School, #2

Tristan took one last look at the horses being prepared for filming and the actors in woollen uniforms emerging from the vans. It wasn't hard to imagine a real war-time recruitment situation. Even less hard was imagining Onyx as one of the horses about to be shipped off to war. Sheoaks Equestrian School has turned into a film set. It should be an exciting time for Monika, Spike, Hattie and Tristan.
Instead, the glamour of the movies is dulled by the actions of the movie's horse master, Katy Wild. Well-educated horses that are easily trained are needed for films, and Sheoaks' riding school horses would be perfect. When Katy takes a particular interest in Black Onyx, Tristan knows she wants to buy him for the World War I film. Why wouldn't she when Australian stockhorses were thought to be descended from Walers, the Australian war horses? What can Tristan do to keep Onyx at Sheoaks?