The River, The Wheel, and The City of the Moon

The Carver family travels to ancient Sumer, in the city of Ur on the Tigris-Euphrates river delta, home to some of the world's first cities.

Yes, it is Book 6 of The Cube Chronicles. It can be read as a standalone adventure, but returning readers will recognize ongoing family traditions and callbacks to earlier crossings (Egypt, the Indus Valley, China, Japan, and more).

The Carver family: Daniel (a builder), Elizabeth (mother), and their children Simeon, Beckah, and Ellie. In Sumer they befriend Igmil (a canal apprentice), Ur-Nin (a canal-master), Shara (a self-taught scribe girl), and Dudu (a young temple musician).

It's the cube's green-gold, rippling glow that signals the family's sixth destination—a river-delta civilization built around irrigation, distinct from the fire, water, and light patterns of prior crossings.

Readers learn about Sumerian irrigation (canals, the shaduf), cuneiform writing and scribe schools, bitumen as a building material, the true arch, the seeder plow, ziggurats, and ancient Mesopotamian music.

Yes. It is a family-friendly, middle-grade historical adventure with strong educational content on ancient Mesopotamia, suitable for classroom units on early civilizations or library shelves alongside other historical fiction.

No graphic violence. There is everyday manual-labor peril (working near rivers and canals, tar burns from bitumen work) typical of historical craft apprenticeship, handled in a mild, age-appropriate way.

Yes. As in the rest of the series, the Carver family is a Christian family who prays and reflects on faith. This volume ties their visit to Ur directly to the biblical account of Abraham, who is said to have come from 'Ur of the Chaldees.'

References to a divine Maker/God appear in the family's prayers and reflections throughout the series, but the Maker is never depicted or shown visibly on the page.

Simeon apprentices in Sumerian canal-keeping and water management, learning to work with bitumen (natural tar) as mortar and waterproofing, build reed boats, and construct a true mudbrick arch.

Ellie learns to play the lyre from a young temple musician named Dudu, discovering how one instrument can carry melody, rhythm, and harmony together.

Daniel's sixth building wisdom is 'build the builder'—teaching an apprentice so that what you build outlives you, mirrored in the recursive, self-sustaining systems (canals, seed crops) the family studies in Sumer.

The River, The Wheel, and The City of the Moon runs about 52,000 words (198 pages in paperback), organized into 30 chapters across four parts: The Delta, The Wheel, The Deep, and The Return.

It closes on the family's usual grateful, reflective return home, but ends with a clear hint that a seventh cube configuration ('tooth') is already forming, setting up the next book in the series.