What happens at the end of the book the Scorpio races?

I actually just finished this book and at the end of this great novel Puck wins the race and Sean does not finish it so once Puck finishes she goes back and tries to find Sesn and eventually finds him and Corr, His horse lying down. Then Corr is starting to go back into the ocean but chooses to stay and live with Sean and Corr cannot race anymore due to a broken ankle