Karana is unable to leave her house for five days because of her leg, but is finally forced to leave when she runs out of water. She has to crawl to the spring, dragging her weapons behind her. On the way, the wild dogs begin to follow her. She is able to scare them away with her bow, and eventually reaches the spring, but by the time she gets there the dogs have surrounded her. Instead of trying to make it home, Karana crawls into a cave near the spring, where she stays for six days, only leaving to get more water, until her leg is healed and she can walk.
Karana decides to make the cave into a second home where she can stay if she is again injured or sick. She knows her ancestors used the cave because it is filled with drawing, but she does not know what for. Karana makes shelves, baskets and a bed in the cave, just as she did in her house on the headland.
After she has finished her new house in the cave, Karana returns to the beach, where she finds the corpse of the old sea elephant. From his teeth she makes four new spearheads. She makes two new spears from these and is finally ready to attack the wild dogs.
The wild dogs on the island grew bolder after the battle with the Aleuts for two reasons. The first is that village dogs whose masters were killed joined the pack. The second is that a large, gray dog with yellow eyes had become the pack's leader. This dog is bigger than the rest, and a different color (most dogs on the island of the blue dolphins have brown eyes and fur). Karana believes that the gray dog is an Aleut dog left on the island after the battle.
In her attack against the dogs, Karana first builds a fire outside the dogs' cave, then pushes it inside to fill the cave with smoke. The dogs run out a few at a time, but Karana saves her arrows for the leader of the pack. When he comes, Karana hits him in the chest with an arrow. She turns and kills two other dogs with her remaining arrows. When she turns back, the gray dog is gone. Karana searches for him, but only finds half of an arrow, gnawed through.
It rains for the next two days. On the third day Karana finds the gray dog, barely alive. She prepares to shoot him but find she cannot; instead she carries him back to her house, where she removes the arrow in cleans his wound. She leaves him with some water and goes to gather food. When she returns, the dog is still alive and has drunk the water. Karana cleans his wound again and gives him some food. That night she sleeps on the rock, fearing that the dog might attack her.
The following day Karana goes fishing, and when she returns to her house she gives the dog some fish. That night she sleeps on the rock again. The next four days she repeats this process, but on the fourth day the dog is not waiting at her fence as usual. To her surprise, Karana is somewhat disappointed, and begins to call out for the dog. When she enters her house, however, she finds the dog inside. That night she sleeps inside the house and decides to name the dog Rontu, which means Fox Eyes.
In this section Karana creates a second home upon the island. Just as building her first home on the island is a marker of her acknowledgement that Ghalas-at is her home, the creation of this second emergency house indicates a preparation for a long stay on the island. She wants to be ready for anything that might befall her during an extended period if she has to wait a long time for the white men to come.
Karana's decision not to kill Rontu is important because it shows how Karana can be unaware of her own motivations. She has no conscious reasons for not killing the dog. As she says, she has the arrow drawn but "my hand would not let it go." In chapter fourteen, Karana and Rontu are bitter enemies. Karana had vowed to kill all of the wild dogs on the island when they killed her brother, Ramo, but when Rontu's pack hungrily follows Karana as she crawls toward the spring to get water, necessity is added to revenge as a motive for exterminating the dogs. Karana's plan of attack against the wild dogs works perfectly, but when she has the chance to finish Rontu, she doesn't take it. Karana describes her hand as an entity separate from her body, something with a will somehow separate from hers, and this description demonstrates just how difficult her own actions are for her to understand. She speculates that perhaps she did not kill Rontu because he cannot move; "if he had gotten up I would have killed him," she says. It seems, then, that Karana does not kill Rontu because he is helpless. She is unable to kill a defenseless creature, even if it has done her a grievous wrong.
Karana's decision to bring Rontu back to her house is almost as mysterious as her decision not to kill him. At least two different causes could have motivated her action. The first is the pity and compassion she displayed in sparing Ramo's life. Leaving Ramo to die is just about the same as killing him, and perhaps the pity sparked in Karana by Ramo's helplessness compelled her not only to spare him but to help him. A second possible motive is the need for companionship. Karana is alone on the island, and though she has the comfort of knowing she is "home," she still has no one with whom she can interact. She may not have brought Ramo home for the express purpose of making him her friend, but this may have been an implicit intention in the back of her mind, and is revealed by her dismay when she thinks he has left. Karana may have taken care of Ramo for either or both of these reasons, or maybe for some completely unrelated reason. The result, however, is some relief to her loneliness on the island.