The Moon Prince is a trilogy of graphic novels telling the story of two bi-racial orphans, Max and Molly, who have been growing up in a workhouse in the town of West Hoboken, New Jersey. The time appears to be around 1900 -- but as we discover, this isn't really the same America we're used to. For one thing, the government is an Aristocracy, with a Queen, and they rule by keeping most of the population half-asleep with something they call "Joy Juice".
Max and Molly encounter an old prisoner who realizes that they are “M’Chawis” - members of a family who can exercise special powers with the help of mysterious “Familiar Stones.” He tells them they have to go to a nearby ferry house and find a concealed map, but their furious overseer beats the old man to death. Soon, Max and Molly find themselves on the run from the Royal Police, who want to know what the old man said.
With the help of Kitiko – a strangely intelligent cat – they manage to find and follow the map to a cottage deep in the swampy Meadowlands, where “Mad Billy” – a member of the shadowy “Resistance” – has hidden an “Aether Ship” invented by the old man. With the Royal forces closing in they narrowly escape in this ship, but are trapped hundreds of miles above the Earth, in orbit, when its power runs out.
Max accidently discovers his special power when he attempts to recharge the ship, sending it hurtling out of control toward the Moon. They manage to land safely - and discover that the Moon is habitable! - but are quickly caught up in a war between pirates and giant bat people, led by Prince Grakko (the “Moon Prince” of the title), who they rescue. Molly discovers her special power, too – she can translate any language and sometimes even read people’s minds.
After many adventures (involving aliens, an underground city and a giant robot) they manage to help their many new friends on the Moon repel an invasion of humans from their home country back on Earth. In the process, they discover a great deal about the history and secrets of the old Solar Empire that had formerly ruled the Earth, the Moon, and the rest of the planets – including some of the reasons it had collapsed thousands of years earlier in a terrible war.