Heaven

On the ocean planet No-Moon, Second-Best Sailor contentedly lives the life of a mariner plying his trade with visiting space-dwelling Neanderthals. When his reefwife discovers that a mission fleet has targeted their homeworld for conversion, his comfortable lifestyle vanishes in an instant.
Servant-of-Unity XIV Samuel has cheerfully devoted his life to the grand wonder that is Cosmic Unity, and all he desires is to help spread its message of universal harmony to a grateful galaxy. But Samuel's awe turns to horror when he uncovers Cosmic Unity's darkest truth.
At its core, Cosmic Unity is a lovely, seductively gentle religion stating that all creatures - whether born of flesh, silicon, superconducting gases, or magnetic plasma - are equal and deserve tolerance. Yet over 22,500 years and spread by a vast hierarchy, the simple concept has mutated into a malignant and violent memeplex - heretics will not be tolerated.
Bereft of faith and rebelling against the Ecclesiarchs, Samuel is shattered and confused when he stumbles upon Second-Best Sailor, fleeing from his threatened home to a potential new habitat. Flung together by fate and supported by the Neanderthals' host of traders, Second-Best Sailor and Samuel plot a kamikaze plan to fight off the invaders. Along the way, they will need the help of the unlikeliest and most fascinating of allies.
But can they bring down an idea that has destroyed everything across tens of thousands of light-years?