The boys had finished their term at Putnam Hall and on their return home became students at Brill College, a fine institution of learning of the Middle West.  At the same time Dora, Nellie, and Grace became pupils at Hope Seminary, located not many miles from Brill.  At the college the Rovers made many friends, including Stanley Browne, already introduced, and Will, otherwise known as “Spud,” Jackson, a lad who loved potatoes, and who also loved to tell big yarns.

A term at college had been followed by a trip down East, taken for a peculiar reason, and then, while on a visit home, the three lads had become the possessors of an up-to-date biplane, which they named the Dartaway.  In the biplane, as related in the volume before this, called “The Rover Boys in the Air,” our heroes made a somewhat spectacular trip from the farm to the college campus, much to the amazement of their fellow collegians and their instructors.  Later they made a trip through the air to Hope Seminary, and at that time Dick was delighted to place upon Dora’s finger a diamond engagement sing.

A short while later an alarming thing occurred.  The boys were out in the Dartaway when they met Grace on the road and learned that Dora and Nellie had been abducted by Josiah Crabtree, Tad Sobber, and some of their other old enemies.  They gave chase in the biplane, and, after several adventures, located the girls in a lonely mansion in the country, where they were prisoners, in charge of Sobber’s aunt The boys at once went for the authorities, and, after something of a fight, the rascals were made prisoners, and the girls were rescued and taken back to the Seminary.

“You will appear against these scoundrels?” asked the sheriff, Jackson Fells, of the Rover boys, as they were about to leave the sheriff’s office at Plankville.

“We’ll appear all right enough,” Tom had answered.  “Why, Mr. Sheriff, you couldn’t beat us away with a club!” And so it had been arranged that the Rover boys should appear in court against the evildoers whenever wanted.  Then Crabtree, Sobber, and the others had been put under lock and key in the old-fashioned country jail; and there, for the time being, the matter had rested.

“I wish we could learn more about Crabtree’s escape,” remarked Tom, as he and his brothers entered the main building of the college.

“So do I,” added Sam.  “Can’t we telephone over to Plankville, to Sheriff Fells?”

“More than likely the sheriff is out, hunting for Crabtree and the others,” answered Dick.  “But I’ll tell you what we might do—­ if the weather stays good,” he added, suddenly.

“Sail to Plankville in the Dartaway?” queried both of the others.

“Yes, if Doctor Wallington will give us permission.”

“He ought to—­ since we are so much interested in this case,” returned Tom.

“We’ll find out, as soon as the morning session is over,” said the eldest Rover boy; and then all hurried to their classes, for the final bell had ceased to ring.