The novel “Through the Eye of a Needle” by Hal Clement was published for the first time in 1978. It’s the sequel of “Needle”.

The Hunter remained on Earth due to the impossibility of getting in touch with his people, who are knows how many light years away. As a result, he kept on living in symbiosis with Bob Kinnaird but after seven years the boy’s body is undergoing a degeneration that the Hunter doesn’t know how to stop and has already become a risk to his health.

Back to his home island, Bob consults with Dr. Seever, one of the very few people who knows about the Hunter’s existence. It’s an unprecedented situation and the only hope is to find someone of the Hunter’s species with enough biological knowledge to restore Bob’s health before it’s too late.