The Poison in the Blood by Tom Holland
The book tells the story of the poisoned arrow that shot Paris (as in Helen of Troy). In the beginning, Earth created monsters. One of these was the Hydra. Heracles killed it, then dipped his arrows in the venom of its blood. Years later, when his wife was abducted by a centaur, he killed the rapist with one of these arrows. The dying centaur told Heracles' wife to dip a robe in his blood, and give it to Heracles as a token of her love. Heracles put on the robe, and was burned alive by the poison. He built himself a funeral pyre, but no one would light it. Finally, a small boy named Philoctetes did as Heracles asked, and Heracles left him his arrows as a reward. It was with one of these arrows that Paris was shot. Dying, he was taken into the woods where there lived a goddess who had once loved Paris, and had the power of healing. But she refused to cure him, and sent him away. Repenting, she then hurried after him, but it was too late.