An expedition is sent to the continent Troltungh, which is concealed by an energy shield. The shield opens to let the terran shuttle in, but closes right after them. The Terrans discover that many different races coexist on the continent, and they were all lured to this planet by the call of the Kelsirens.

When the Terrans start threatening to disturb the order that reigns on the continent, the Empress of Therm opens up the shield and agrees to let them go.