The Good Morty appeared in the episode Close Rick-Counters of the Rick Kind. It is a sacred text, talking about Mortyism, an interdimensional religion that is intended only for Mortys to follow. A cult following of Mortys has read the book and takes their values from it, believing it's contents to be true and obeying the rules that it tells them to follow. The book is read by a group of Mortys in a dungeon/torture chamber located on a distant planet, where Mortys are constantly tortured by Evil Rick. The book tells the Mortys that they will one day be relieved of their suffering, upon the arrival of a holy prophet, known only as The One True Morty.