Mystery of the Soulriders follows four girls as they combat evil forces in their town through the power of friendship; both with each other, and with their magical talking horses. The game opens with Lisa, on her first day of school, helping the horse Starshine ride again. But who is the old man Mr. Sands, and why does Starshine feel pain whenever he is near?

The main character in the first episode is Lisa, who has just moved to Jorvik with her father. We start the game on her first day in school where she needs to find the janitor, so she can go to her first class. On the way she meets Anne, Linda, Alex, and the unusual Sabine. Soon she obtains Linda's stolen locker keys, who were dropped by Sabine. Even though she is scared of horses because of a riding accident, she goes to Jorvik Riding School to return the keys. There, she meets Anne and Sabine once again together with Herman, the owner of the stables. In her search for Linda she finds the sick horse Starshine, whom she immediately bonds with. When Starshine later disappears, Lisa does everything she can to find her new friend.