Return to Trinity where Earth had first discovered intelligent life that allowed them admittance into the Cooperative League of Systems. Through friendship and understanding the men and women of StarBridge are forming bonds with the natives. In the skies of Trinity, the birdlike Grus welcome the deaf human ambassador, Tesa. In the seas of Trinity, the aquatic Singers communicate with the young StarBridge student, Jib. But on the surface of Trinity, an alien life form has landed, and these amphibious beings from a distant world are definitely not friendly.
Deaf since birth, Tesa is the perfect ambassador to the alien Grus, whose sonic cries can shatter human ears. But her mission is harder than it looks. The Grus are not alone on their world.They have deadly enemies, both natural and otherwise. And if Tesa is to save all life on the planet, she will have to make peace with not one alien species...but two.