Return to Quag Keep is an independent sequel to Norton's Quag Keep and continues with the same characters and in a similar role-playing game style. However, this time the characters have a little more depth to them, and the plot is more complex. The swordsman Milo Jagon, the berserker Naile Fangtooth, the elf Ingrge, the bard Wymarc, the cleric Deav Dyne, the lizardman Gulth, and token woman, the battlemaid Yevele, are all originally from our own world and were transported into the fantasy world and the characters they had been playing when they touched miniatures that resembled their characters.

The book starts with the priest and the lizardman saying goodbye to the rest of the group. Gulth is dying in the dry climate and needs to leave for his native swamp; Deav wants to go with him to make sure he survives the journey. Meanwhile, Naile and Milo are drinking in a tavern. Since they do not have any money, they are hoping that they are going to be hired before the bill comes. Instead, they get into a brawl and wake up in a jail cell with a hefty fine to pay. Luckily, a rich merchant pays their fines and drafts them to guard his caravan, having earlier hired Yvele and Ingrge as guards as well. The bard chooses to stay behind and sing to make up for Naile's and Milo's bill for breaking up the tavern. Shortly after the caravan leaves the city, Wymarc is murdered.

On the way, the caravan is attacked by an army of undead and the scouting Ingrge stumbles upon a thief, Berthold of the Green, who says that he came from the real world just like the main characters. The thief claims that they must come with him in order to save a world and possibly find a way to return to their own. The key is to get back to Quag Keep and rescue a wizard who is held there. They decide to split the adventuring party again. The thief, Yvele and Ingrge leave to find Quag Keep again while Milo and Naile stay to pay off their debt as guards.

This time the characters' personalities stem mostly from the gamers' own personalities. However, they get skills and knowledge that their gaming characters have, as well as fearlessness in battle. Also, their real world memories are fading, and most of them find this scary. They talk more about themselves in the real world and all of them seem to be adults. Although the characters talk about gaming and how monsters and other things are in the game, the mechanics themselves are not part of the story as they were in the previous book. Readers who are gamers themselves might be highly amused by the characters' banter about the gaming.

The point-of-view characters can shift quickly, even within a single paragraph although most of the time a chapter or a scene will keep to just one POV character. Out of the five characters shown most - Milo, Naile, Yvele, Berthold, and Ingrge - Yvele is the only one whose POV is shown but rarely.

Much like in the Quag Keep, the group is pitted against a wide variety of monsters - but this time they also have to face traps, because there is a thief in the party. It is a quick, light read for people who enjoy role-playing game fantasy.