In the end Dave "took the law in his own hands" by giving Link Merwell a sound thrashing.

Then some of the bully's wrongdoings reached the ears of the master of the school, and he was ordered to pack his trunk and leave, and a telegram was sent to his father in the West, stating that he had been expelled for violating the school rules.

He left in a great rage.
"This is the work of that miserable poorhouse rat, Dave Porter," Link told some of his cohorts.

"Just wait--I'll fix him for it some day, see if I don't!" Then he wrote a most abusive letter to Dave, but in his rage he forgot to address it properly, and it never reached the youth.
The term at Oak Hall came to an end in June and then arose the question of what to do during the vacation.

In the meantime letters had been flying forth between Laura and her warm friend, Belle Endicott, who was still at Star Ranch, as Mr.Endicott's place was called.