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.