The morning after the evening when Frank saw the mysterious stranger in front of Traeger's he received a warning note through the mail. It read as follows: "Be constantly on your guard. Your enemies are plotting to do you serious injury. I shall do what I can to foil them, but you had better watch out." It was unsigned, and the handwriting was cramped and awkward, as if the person who wrote it was not accustomed to handle a pen. "Well, I wonder what sort of a game this is!" cried Frank, in disgust. "It is a fake, pure and simple!" Rattleton was at his side. "What is it?" asked Harry. "Read that!" invited Frank, thrusting the anonymous warning into the ready hands of his friend. Harry glanced it over and then whistled softly. "Rot!" he cried. "Anybody can see that's lot on the nevel--I mean not on the level." "But what sort of a game is it?" questioned Frank, in perplexity. "If it was an appointment to meet somebody somewhere, or even a warning to stay away from some place, I could see something in it; but the mere statement that enemies are plotting to injure me doesn't indicate much in this case." "It seems to indicate that somebody fakes you for a tool--no, takes you for a fool!" spluttered Rattleton. Frank's face grew scornful. "That somebody may find out that it is not entirely healthy to try crooked games with me," he grimly said. "I believe I see through the trick." "What is it, then?" "This bogus warning will be followed by another. The other will go a little further than this. Then will come the third, which will be the one intended to draw me into some sort of a trap. Oh, the game is too thin!" Harry looked into his roommate's face, and saw that Frank Merriwell was aroused at last. "What are you going to do?" asked Rattleton. "I am going to have a few words with Fred Flemming at the first opportunity. I have been easy with Flemming, for I could not believe the fellow all bad, even though he had tried to injure me, but, if he is going to hire a ruffian like this unknown man to try to work my ruin, I shall draw the lines on Mr. Flemming. He is rich, but that will not save him." "They say he has money to burn." "I don't care if he is a Monte Cristo. He cannot ride over me with all his money, and I do not believe that a scoundrel will be tolerated at Yale after his villainy is exposed, even though he may be rich and have influential parents and connections." "What do you think the game is?" "As to that I am more or less at sea; but I believe that the bribe which was offered me to throw the ball game to Harvard was a trap meant to work my undoing." "Flemming must have known your hand would not permit you to play in that game, so he could not have been in that piece of business."