“Well?” asked Cahill.

“I must first explain to Lieutenant Ranson, father,” said his daughter, “that to-day is the day we take account of stock.”

“Speaking of stock,” said Ranson, “don’t forget that I owe you for a red kerchief and a rubber poncho.  You can have them back, if you like.  I won’t need a rain coat where I am going.”

“Don’t,” said Miss Cahill.  “Please let me go on.  After I brought you your breakfast here, I couldn’t begin to work just at once.  I was thinking about—­something else.  Everyone was talking of you—­your arrest, and I couldn’t settle down to take account of stock.”  She threw a look at Ranson which asked for his sympathy.  “But when I did start I began with the ponchos and the red kerchiefs, and then I found out something.”  Cahill was regarding his daughter in strange distress, but Ranson appeared indifferent to her words, and intent only on the light and beauty in her face.  But he asked, smiling, “And that was?”

“You see,” continued Miss Cahill, eagerly, “I always keep a dozen of each article, and as each one is sold I check it off in my day-book.  Yesterday Mrs. Bolland bought a poncho for the colonel.  That left eleven ponchos.  Then a few minutes later I gave Lightfoot a red kerchief for his squaw.  That left eleven kerchiefs.”

“Stop!” cried Ranson.  “Miss Cahill,” he began, severely, “I hope you do not mean to throw suspicion on the wife of my respected colonel, or on Mrs. Lightfoot, ‘the Prairie Flower.’  Those ladies are my personal friends; I refuse to believe them guilty.  And have you ever seen Mrs. Bolland on horseback?  You wrong her.  It is impossible.”

“Please,” begged Miss Cahill, “please let me explain.  When you went to hold up the stage you took a poncho and a kerchief.  That should have left ten of each.  But when I counted them this morning there were nine red kerchiefs and nine ponchos.”

Ranson slapped his knee sharply.  “Good!” he said.  “That is interesting.”

“What does it prove?” demanded Cahill.

“It proves nothing, or it proves everything,” said Miss Cahill.  “To my mind it proves without any doubt that someone overheard Mr. Ranson’s plan, that he dressed like him to throw suspicion on him, and that this second person was the one who robbed the paymaster.  Now, father, this is where you can help us.  You were there then.  Try to remember.  It is so important.  Who came into the store after the others had gone away?”

Cahill tossed his head like an angry bull.

“There are fifty places in this post,” he protested, roughly, “where a man can get a poncho.  Every trooper owns his slicker.”

“But, father, we don’t know that theirs are missing,” cried Miss Cahill, “and we do know that those in our store are.  Don’t think I am foolish.  It seemed such an important fact to me, and I had hoped it would help.”

“It does help—­immensely!” cried Ranson.