The most logical conclusion to the story, considering the theme of good sportsmanship, would be:
Nell exposes the lie and proves that Hamish is innocent, allowing the friends to compete against each other.
This outcome aligns with the values of fair play and integrity, showcasing Nell's commitment to supporting her friend and ensuring that the competition is just. It emphasizes the importance of standing up for what is right, even when it might personally benefit her to remain silent.