Welcome to an enchanted land ruled by unicorn princesses! Cressida Jenkins, a unicorn-obsessed girl who is sure that unicorns are real, is invited to visit, and readers will be thrilled to journey to the Rainbow Realm along with her! In each story, Cressida is called to help a unicorn princess and her sisters in a magical adventure.

In Flash's Dash, the annual Thunder Dash is approaching, and Princess Flash has opened the race to non-unicorns for the first time ever! Cressida is the first human girl invited to participate, but Ernest the wizard-lizard accidentally casts a spell that covers the race track in sticky, pink goo! Can Cressida and the unicorn princesses find a way to save the race?