Summer has always loved horses, and she's longed for the day when she'd be able to ride a pony of her own. So when Summer meets Jessie and gets a chance to visit the Starlight Stables, she leaps at the chance. Helping out at the stables is a dream come true, until her favourite dapple-grey pony, Luna, gets stolen. With a thief on the loose, and suspects round every corner, it's up to Summer and the rest of the Starlight Stables Gang to rescue Luna before it's too late!