As you may guess from the title, there's a certain amount of role-playing games involved in this fantasy. (NPC being short for non-player character.)
It opens with a prologue to be significant later, and then the first chapter starts with a party arriving at a tavern. Russell is doing his best to make it vivid but the players are three Munchkins (think the games is about winning fights and loot) and a newbie who's a bit diffident about standing up to them, even though he's playing a paladin. The characters have a drink. They learn that the mushrooms they ate, despite finding on a critical fumble, are poisonous.
To them, an occasion to roll up new characters. (Though they will reappear later -- after a gap that I think probably should have been shorter.) For the four NPCs in the tavern, a disaster. The party had a scroll from the mad king who will slaughter the villagers and destroy the village for the suspicion of poisoning the party. They realize that they can protect the village. And even have a remote chance of surviving themselves.
So we have four NPCs trying to blunder their way into being adventurers. It's not so self-aware as Order of the Stick -- but we have a tournament, some goblins, a discovery that they misassigned who was what adventurer, the secrets of being a minion, and more, before we find out the significance of the prologue.
Adventures, heroism, and some humor.