Mystery at Brightfields

After Pin leaves at the end of season 2, where does that leave Zoe, Raven, and Brightfields?
Big news for Zoe and the family and a life changing competition coming up for her and Raven.
After the construction of the barn is completed and Pin extends his "travel the world" trip, a mystery horse shows up at Brightfields and no one knows where it came from or the secrets that it has. Suprises follow and Pin eventually returns. What now?

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