Margaret Wander Bonanno 
Dwellers in the Crucible [EPUB ebook] 

DWELLERS IN THE CRUCIBLE Warrantors of Peace: the Federation’s daring experiment to prevent war among its members. each Warrantor, man or woman is hostage for the government of his native world – and is instantly killed if that world breaks the peace. Now Romulans have kidnapped six Warrantors, to foment political chaos – and then civil war – within the Federation. Captain Kirk must send Sulu to infiltrate Romulan territory, find the hostages, and bring them back alive – before the Federation self-destructs!