The Life of Stars (Book 2 in the Apollo series)

'He could feel it thumping in his chest, though whether it was because of activity, anger, or something else entirely, he didn't know. Nor could he tell. His beating heart only told him he was still alive. How alive though- that was a different question.'

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Hyacinthus was the prince of Sparta. He thought he had everything he could ever want, until he met Apollo, and he realised that he had nothing at all.