This review may contain spoilers. I can handle the truth.
In the first shot we see, how Franz von Hübner (Attila Hörbiger) shoots his horse. On trial he tells in a series of flashbacks the story of his horse Maresi (the nickname of empress Maria Theresia) and the love story with the young Blanka von Steinville (Maria Schell) which is always connected with the fate of the horse.
The adventures of Maresi range from a short lived career on the racetrack as well as serving in World War One (Maresi is part Seabiscuit and part War Horse you might say). The social decline of von Hübner is mirrored by the harsh fate of Maresi who is finally abused by a coach driver. Something the now penniless von Hübner can't stomach and he shoots his beloved Maresi.
With it's overly sentimental style this is a very typical movie of the 1950s Austrian movie landscape. Hörbiger and Schell are okay, but they are playing characters I could never get behind.