The CLUSTER series of SF adventures is set in a future focused on colonization of distant planets. Sphere Sol is about 100 light years in diameter, centered on the Earth’s sun. Surrounding this sphere are other, similar spheres each centered on another star such as Polaris or Canopus. Colonization is accomplished by: instantaneous teleportation, called matter transmission or mattermission (very expensive); “freezer” ships in which colonists are sent in cryonic preservation at very high speeds (much decay and average 50% loss of colonists occurs during the voyages) and lifeships, slower, safer multigenerational vessels with voyages that run to centuries (during which the travelers regress in technical sophistication.) Because of the difficulty of colonization and the smaller population bases, all spheres suffer spherical regression--the greater the distance from source star to colony, the lower the level of technology that survives. Social organizations regress backward to historical periods of the home planet's past. Outworld, Sphere Sol's farthest colony, is populated by paleolithic tribes who hunt with flint spears and make fire. Colonists know about the interstellar empire and the home worlds mattermit government and security personnel to all colony worlds. Every living thing has a Kirlian aura that can be measured. Through transfer, a refinement of mattermission technology, the mind and personality of individuals with high aura can be sent to animate a body physically distant but a hosted aura fades at the rate of about 1 unit per Earth day and higher-Kirlian individuals last longer and thus have more freedom of movement. The first three novels in the sequence, CLUSTER, CHAINING THE LADY and KIRLIAN QUEST form a linked trilogy. THOUSANDSTAR and VISCOUS CIRCLE came later and take place in the time sequence between the second and third volumes of the original trilogy. On the world called Eccentric a new Ancient Site has been discovered, and unlike others which are "dead" this one appears to be active and functioning. To determine which Sphere has the right to explore it and investigate its secrets, a competition is being held. Each competing team consists of a carefully-matched host and transferee pair, chosen for their complementary skills and knowledge. The tasks test all of the competitors' abilities to their limit and range from word puzzles to navigating past a black hole. However, both Heem of Highfalls and his transferee Jessica of Capella have deep dark secrets that may cost them not just the competition but their lives.