The Cave Girl is an Edgar Rice Burroughs adventure that puts an effete New England blueblood on an island of cavemen. Hilarity ensues, as do over-the-top action set-pieces.

At one point, Waldo Emerson Smith-Jones is chased by cavemen up the side of a cliff. The way to turn this into a D&D encounter is to have your battlemat represent a vertical plane.

The battle starts with the PCs pursued by an overwhelming number of tough minions (they do 2x normal minion damage).

Everyone starts at one end of the battlemat (ground level). The PCs are trying to get to the other end of the battlemat (the top of the cliff).

Traversing most squares involves Climb checks. Drawn on the battlemat, however, are a maze of platforms connected by horizontal, diagonal, and vertical ladders. Movement along platforms and ladders follows normal walking rules.

On every platform is a stack of rocks. The rocks attack everyone in a vertical line when dropped; this is useful because the pursuing minions often line up vertically, especially when climbing ladders. PCs can also push ladders over, sending climbers to their deaths.

At the back of each ledge is a cave. The PCs don’t know whats in each cave, but the cavemen do. Some caves connect together; one has extra treasure; and one has an escape route from the encounter.

The mannered country-house farces of PG Wodehouse don’t lend themselves very well to adaptation as D&D adventures because they rely on intricate, delicate plot, which is hard for a DM to sustain, and a very specific dialogue style, which is hard to pull off on the fly (and if you think you’re managing it, you just might be making yourself annoying).

The beautiful spun-sugar plot constructions might not be usable, but the general premise of a Wodehouse novel is very thematic to D&D: “Idiot or idiots get into hilarious mishaps through a series of misunderstandings, overcomplicated plans, and bad judgement calls.” This is a perfect description of PC activity whenever combat is not involved.

Leave it to Psmith relies on one plot device that is usable in a D&D game: mistaken identity. Psmith and two other characters all claim to be a poet named McTodd; one of the other two claimants is actually McTodd, and one is an American gangster.

Try offering this as a puzzle for the PCs. They’re instructed to, say, give a powerful item to a certain NPC named McTodd. They find two McTodds, each claiming that the other is the imposter.

The two NPCs both have fairly good knowledge of their role, and differentiate themselves mainly by their attitudes. McTodd 1 is sputtering and angry: “How dare this imposter speak to me in my own house!” McTodd 2 seems amused by the situation and speaks flippantly: “You say I am not McTodd? Well, perhaps I am not. I’ve been wrong before.”

Various knowledge checks provide conflicting results: McTodd 1 explains a sudden disinclination for cake as the effects of a recent illness; McTodd 2 seems to have forgotten some obscure detail of his own history.

The gimmick here is that the DM does not know which McTodd is the real one either. The DM is keeping track of two separate possibilities, but until the PCs concoct a plan that will absolutely solve the mystery, it is a case of Schrodinger’s McTodd. If another NPC corroborates one McTodd’s identity, that NPC exists in an indeterminate state as a honest man/villanous accomplice.

When the DM must finally pick a real McTodd, the choice is made by a die roll or coin flip.

Many players are very good at picking up on unconscious hints from the DM. Mysteries can be solved, not by the clues, but by the DM’s tone. If the DM doesn’t know the solution to the mystery, though, any such clues will be misleading.