Mission to Minerva

Earth is adapting to a future of amicable coexistence with the advanced aliens from Thurien, descended from ancestors who once inhabited Minerva, a vanished planet of the Solar System. The plans of the distantly related humans on the rogue world Jevlen to eliminate their ancient Terran rivals and take over the Thurien system of worlds have been thwarted, but the mystery remains of how it was possible for the fleeing Jevlenese leaders to have been flung back across space and time to reappear...