Zi's Distant Discoveries — Robert L. Collins

An urgent message has arrived for Zi and Ysina. The ape-folk they freed in their first adventure together report strange lights and missing Chiefs. Ysina is Princess and has to raise their daughter, so Zi offers to go south. Once there she tries to find the missing Chiefs, build peace with the ape-folk, and figure out why strangers from far away are so interested in the colored stones that Chiefs and their mates wear around their necks.