"I presume he's rather keyed up because the circus is coming here tomorrow," Nancy remarked.

"To tell you the truth, Miss Drew, Hitch is beside himself. He has declared he won't go near it, but I wonder if he can resist. Anyway, I'm going. I want to see what acts they have now and say hello to my old friends."

As Roberto finished speaking, Hitch led Nancy's mare into the ring. The beautiful gray horse nuzzled the girl as she stroked the animal's velvety nose and murmured:

"Belgian Star, you sweet old thing! We're going to have a good lesson today."

Nancy swung into the saddle and walked her horse counterclockwise several times around the ring. Then Señor Roberto called out:

"Trot!"

Automatically, Nancy sat still for a few strides, then started posting, remembering to take the up motion when the mare's left foreleg was forward in order to get the correct diagonal. The riding master smiled in satisfaction at the rhythm and grace of Nancy's performance.

Next came the canter. Half an hour later, Nancy was ready for stunt riding. First, Hitch removed the saddle, looking darkly at Nancy as he carried it away.

Once more she mounted the horse, this time with only the blanket between her and the mare. Nancy slapped her gently on the flank and the horse began to canter slowly. Being an ex-circus horse, Belgian Star was considerate of her rider.

She seemed to know just the right speed to use, too, as Nancy stood up on the mare's back. Keeping her balance, Nancy went twice around the enclosure. On the third lap she caught a fleeting glimpse of a figure crouching on the ground outside the split-rail fence.

The next moment, a rock sailed through the air directly at Belgian Star's head. The horse reared almost straight up, and Nancy was thrown off.

CHAPTER IIA Suspicious Groom

On the far side of the ring Señor Roberto had witnessed the accident in alarm and dismay. He rushed toward Nancy, who lay still on the turf where she had fallen. As he reached her, the girl's eyelids flickered open.