Henry rescues a dog that he finds drowning in the water while he was out in his canoe. He brings the dog in the house and feeds it. Then his dad walks in and tells Henry to get rid of the dog because it would bring trouble.
Henry and Franklin talk about climbing Katahdin, a large and steep mountain in Maine. Henry says he is ready for the climb, but Franklin tells him that he is not ready. Henry argues with Franklin about whether or not he is ready for the climb.
A few days before Henry and Franklin planned to climb Katahdin, Franklin was struck by a car while out jogging. He is in horrific condition and he is all bloodied and bruised.
Franklin's last word was "Katahdin." Henry knew he had to climb Katahdin to prove his worth to his brother. He has been trying for so long to prove himself, and he knew this was his chance to prove himself.
Henry reaches the top of Katahdin with his sister--Louisa--, the boy who killed his brother--Chey--, and his best friend--Sanborn. He finally feels like he has proven himself to his brother, Franklin.