The Blue, Blue Hills of Xuhl

At the heart of the story is the romance between Brogan, a Terran male pilot and Zalina, a female shape-shifter and the Xuhlan ambassador to Merkal.

Brogan is a pilot employed by Inter-Galactic Mining to ferry cargoes of ore back to Merkal from the outer perimeter of the Realm of the Five Planets (Terra, Merkal, Venool, Kanoor and Muliphan). Returning from his 13th trip, he brings some artifacts bought from an old miner on Proxanthus-6 and a dealer on Merkal urges him to take them to one specific buyer and to go at once and be very careful as the objects have great value.

Arriving at the business premises suggested by the dealer, he meets the Xuhlan, ostensibly a trader in off-world artifacts, but also the Xuhlan Ambassador to Merkal. Brogan has never even heard of Xuhlans and is immediately entranced by Zalina; " ... but all of these were incidental; nothing mattered except the incredible, beautiful eyes; large velvet black ovoids with bright, vertical, golden pupils." He agrees to be hired as a pilot and is drawn into a world of romance, intrigue and conflict with aliens from Jonos, a world near Xuhl, 68 light years away from the Five Planets through a 'rift in the fabric of space-time beyond Muliphan'.

On route to Xuhl, two Jonosian agents capture Brogan on Muliphan and torture him causing an enraged Zalina to track them down and slaughter them. On arrival at Xuhl, the Xuhlan High Council authorizes a reconnaissance mission to the Jonosian system to try and determine the Jonosians' strength and purpose and concludes they are preparing an invasion of Muliphan. While on Xuhl, Brogan is persuaded to undergo "the symbiosis" a bonding with the blue native Xuhlan plant life that will give him improved health and increased longevity through the alien DNA introduced into his body which will destroy all invading, harmful micro-organisms. Brogan knows this will inevitably tie him forever to Zalina and Xuhl.

The Xuhlan High Council order direct action to neutralize the immediate Jonosian threat and send Zalina and Brogan back through the wormhole to the Five Planets to inform the high councils on Muliphan and Merkal of the danger and to take a Xuhlan diplomatic delegation to Terra. Returning to Xuhl, they arrive in time to prevent a Jonosian attack on Xuhl and they are able to offer help to their enemies to deal with the problem which caused them to contemplate invading Muliphan.

There are humorous subplots in the romance between Brogan's virile buddy Cisco Marquez and Zalina's friend Shulan and in the investigation on Muliphan into the death of the two Jonosian agents.