The narrator, a dog named Enzo, begins the story with a discussion of how he must communicate through gestures, since he's not able to form language with his long tongue. This need to rely on gestures is why he's currently lying on the floor in a puddle of urine, waiting for Denny (his owner) to come home and find him.
Enzo makes it extremely clear from the very beginning that he's not human, and the extent he must go to communicate with humans because of this. This will be one of his primary concerns throughout the text.
Enzo is old, but he says he doesn't really want to get any older. He believes that Denny would do whatever it took to keep Enzo alive, but Enzo doesn't want to be kept alive. Enzo says this is because of the second-best thing he ever saw on television—a documentary on Mongolia, which said that when a dog is finished being a dog, he will be reincarnated as a man. The best thing Enzo ever saw on television, he says, was the 1993 Grand Prix of Europe, in which Ayrton Senna drove like a genius in the rain. Enzo continues, saying that he's always felt almost human and different than other dogs.
This is a broad intro to Enzo's belief system, which is made up of elements gleaned from watching television and being involved in racing. Enzo's goal is to eventually become human, which will allow him to participate in all the activities he sees on television. Television here acts as a symbol for Enzo's education and belief system.
The door opens and Enzo hears Denny call for him. Usually, Enzo gets up despite the pain, but he uses humanlike willpower to hold back and not get up. Denny calls for Enzo again, sounding concerned, and finally comes into the kitchen. Enzo wags his tail feebly. Denny sets down his shopping bag and reaches for Enzo, touching Enzo's head and asking him what happened. Enzo tries to get up, but finds he truly can't, which sends him into a panic. Enzo believed he was acting, but the act is real. Denny presses on Enzo's chest to calm him and tells him to take it easy before lifting him. In Denny's arms, Enzo smells Denny's day on him. Smelling beer, Enzo experiences a moment of clarity. He says that usually he's very good at marking elapsed time, but today he wasn't paying attention because he was "emoting."
Notice Enzo's insistent focus on storytelling and acting. He's acting to communicate and tell a story for Denny, and he's able to piece together the story of Denny's day by picking out the different smells on him. However, we see how old and ill Enzo really is, as it becomes obvious that Enzo's act isn't really that far away from the truth. Enzo's quips about humanlike willpower and "emoting" set up a hierarchy, with humans and humanlike qualities above canine qualities like "emoting."
Denny places Enzo in the bathtub and apologizes for being late. Denny trails off, and Enzo realizes that Denny believes Enzo's accident happened because Denny was late coming home. Enzo digresses into how difficult communication is; there's presentation and interpretation involved, and the two are dependent and make things harder to understand. Enzo's intent was to show Denny that it's okay to let Enzo go, now that Denny is through what he's been going through. Enzo says that Denny is brilliant and he needs to let Enzo go so he can go on and be brilliant. He remarks that he'll miss Denny and Zoë, but can't let sentimentality get in the way of his plan.
As we're introduced to Enzo's family, we see how much they mean to him and how he's willing to essentially sacrifice himself to allow them to have a better life. Again, consider how Enzo talks about communication and language. For him, as a dog unable to speak, communication is tied up entirely in acting and performance, hence his previous statement that gestures are all that he has.
After Enzo's bath, Denny sets Enzo up in front of the TV, and asks if he'd like to watch a tape. Enzo replies he would, but Denny of course doesn't hear him. Denny puts in a tape of one of his old races, one of Enzo's favorites. The track starts out dry, but as soon as the race starts, it starts to rain. The other cars spin out of control, but Denny drives as though the rain doesn't affect him at all, just like the 1993 Grand Prix of Europe, in which Ayrton Senna passed four champion cars on the first lap like he was magic.
Notice the conflation of Denny and Senna, particularly in relation to their abilities driving in the rain. Rain and water will be a symbol for strife and conflict later, and here we see that both Denny and Senna are capable of overcoming conflict.
Enzo says that Denny is as good as Senna, but nobody notices Denny because he has responsibilities: his daughter, Zoë, and Enzo, and until she died, his wife, Eve. Denny lives in Seattle and has a job, but sometimes he goes away and comes home with a trophy and shows it to Enzo. At these times, Denny tells Enzo about the races, and tells him about what driving in wet weather is truly about.
The pull between racing and family will be a recurring conflict throughout the novel. We also learn now that Eve has died, which allows the reader later to engage with her story while knowing the ending.
After the tape ends, Denny suggests he and Enzo go out. Denny helps Enzo stand, and the two leave the apartment. They only go down the block and back because Enzo is in so much pain. When they return, Enzo curls up in his bed. Denny calls his friend, Mike, and asks him to cover for him tomorrow so he can take Enzo to the vet. Enzo says that they've been going to the vet a lot for medications that don't really work to make him more comfortable. In light of this, Enzo has now set his Master Plan in motion. Still on the phone with Mike, Denny's voice changes and says that he's not sure it's a round trip visit to the vet.
We see, as Denny also does, that Enzo is not in good health. His pain management strategies are obviously not working, and this has led Enzo to formulate his Master Plan—which we can assume includes dying. This is also the first introduction to Mike, who will play a major supporting role in Denny and Enzo's lives. Note that Denny shares his fears that the trip is “one way” only with Mike.
Despite having set it up, Enzo is surprised to hear Denny say this. Enzo knows it's the right thing for all involved, since Denny has done so much for Enzo. Enzo says he feels it's time to set him free; they had a good run that's over now. Enzo closes his eyes and half listens to Denny in the bathroom. He remarks that people sometimes cling so hard to their rituals.
Enzo will return later to the idea of repetition and rituals and why they're so appealing to both people and dogs. Here we see that Enzo interprets Denny's evening bathroom ritual as something comforting for him to cling to.