Francie is thirteen and two important things happen this year: war erupts in Europe (the start of World War 1), and a horse falls in love with Aunt Evy.
You remember how Aunt Evy’s husband, Uncle Willie Flittman, is always battling with his horse? According to Willie, the horse likes to pee on him on purpose.
On cold winter days, Evy thinks it’s really mean that Willie washes the horse with cold water. Drummer—the horse—seems to know that Evy is sticking up for him.
One day while washing the underside of the horse, Willy thinks he is going to get peed on and punches Drummer. In return, the horse kicks him in the head, knocking Willy unconscious.
Willy’s boss decides to hire someone else, but Evy begs and pleads with him to let her do the job until Willie is well again. Eventually, the boss agrees, and Evy becomes the first milk woman on the route.
She does a fine job, and she treats Drummer wonderfully.
She covers him with a blanket when she leaves him outside to eat her dinner, heats up his oats, gives him a treat after his meal, and washes him in the stable with warm water and mild soap. The horse never pees on her. He loves her and all the other workers love her, too. But Willie eventually recovers and comes back to work.
Drummer refuses to take Willie back and won’t move with him in the seat. The boss ends up giving Willy another horse and another route.
They try other drivers, but Drummer still won’t budge without Evy.
Finally, Drummer consents to being driven by a man who is a little more feminine than the others.
Every afternoon, Drummer pulls the wagon out of its way to stop by Evy’s house on the way back to the stables. He won’t continue to go back to the stable until she comes out and gives him a treat. It's true love.