Anna and the Pony Pals have a new job of watching Mimi and her horse and teaching her how to care for her pony, but Mimi may not be able to keep her pony, because she doesn't like to do her chores.
When the Pony Pals find a stray cat, they let him stay in Dr. Crandal's animal clinic until they can find him a good home, but when the clinic catches fire, the cat disappears and the Pony Pals have to find him before he gets seriously hurt.
When Lulu's pony, Snow White, get sick and runs away on the night of a big snowstorm, she must call on her Pony Pals, Anna and Pam, to help her find her runaway pony.
Since Anna loves Ms. Wiggens' pony Winston, she is happy when Ms. Wiggens asks the Pony Pals to take care of him while she is away. Winston is very sick and may die, and now Anna needs her fellow Pony Pals more than ever.