While spending the summer at her grandmother's farm, a girl discovers a talent for communicating with horses and tries to tame a fierce stallion.

Summer vacation. Mika is overjoyed to see Windstorm again. But then she discovers strange wounds on the belly of Windstorm, for which no one has an explanation. Yet this is Kaltenbach verge of bankruptcy! With a heavy heart Mika decides to participate in a variety tournament in which beckons a high prize money. But during training affects Windstorm distracted, often he runs away easily. Mika pursued the black stallion until deep into the forest and is quite surprised: From the thicket a seemingly magical gray mare appears and the two horses dance around lovingly. Suddenly, a strange boy named Milan appears, who says the mare had escaped him. He claimed that he could Help Mika to win the tournament. But is there still time to save Kaltenbach?

Grandmother Maria, Sam and the riding instructor Kaan are trying together to keep Gut Kaltenbach running, which is in financial difficulties. The ambitious Isabell supports her, although she secretly pursues her own goals. The impulsive Ari comes to riding training in Kaltenbach, where she develops a special relationship with Windstorm, the eponymous horse of the film series, and she also makes friends with Mika. Mika and Ari try to save the estate and protect Windstorm from reckless horse trainer Thordur Thorvaldson.

The battle-worn German ace known as Der Ostwind, stops at nothing in his pursuit of a mysterious and invincible American pilot across the war torn skies of WWI.

Due to the sudden outbreak of a hurricane, a traveling circus, famous for its stunning numbers with horses, calls into the small German estate of Kaltenbach. Soon, Ari realizes that one of the horses of this circus, named Orcan, is in mortal danger. Together with the boy Carlo and their faithful friend, the horse Ostwind, they try to save Orkan from the cruel owner of a traveling circus. However, the shrewd director unravels their audacious plan. And Ostwind's horse is also in trouble. Ari and Carlo have very little time to rectify the situation and save Ostwind.

Ostwind and Mika have found a real home at the farm Kaltenbach with Mika's grandmother. In the hustle of running therapy center and due to Mika's fame as a horse-whisperer, she feels that she doesn't have enough freedom and time to ride. After a serious disagreement with her grandmother, Mika secretly sets off for the night in eastern Andalusia, Spain, where she suspects Ostwind's roots are.