play report - Rat catchers in the Rookery

11 Oct, 2026

From the Itch page for Ratcatchers in the Rookery:

Ratcatchers in the Rookery blends elements taken from Luke Gearing and David Hoskin’s Swyvers , the 1977 sci-fi roleplaying game The Realm of Yolmi’s bestiary, and Chris McDowall’s Into the Odd and Electric Bastionland into an homage to the Caves of Chaos from Keep on the Borderlands

It uses those games’ spark tables, name tables, treasure tables, bestiary, and the generative properties therein to create something unique.

Interpreting the module

(if you just want to read the play report, it's further down, just scroll past this.)

Ratcatchers requires interpretation. The first stumbling block is that it uses an intriguing blend of stats that requires conversion work if you're planning to run it in Swyvers, as I was. The primary work of conversion was switching from descending AC in the statblocks to Swyvers' proprietary system of AC-as-Initiative. It turns out it's not as simple as subtracting the NPC's descending AC from 20, as this produced overly inflated DEF values.

My adapted encounter tables.

If you are doing something similar, I'd say your best bet is to

• Set DEF according to the NPC's weapon or closest analogue (claws = sword or shank, etc)
• Have a table handy that converts AC to armor type, then assign the appropriate Swuvers armour die for that armour type.

Here's a handy dandy conversion table:

The second point of contention is with the map. It uses the original map for the Caves of Chaos, which was handy for me because I've been running a B2 game for a while now so I'm familiar with the dimensions of the space. There were some issues, however, with translating it to an urban setting.

B2 gives you 264 words of read-aloud just to set the scene as you enter the ravine that houses the Caves of Chaos, followed by 2 columns worth of contextual information for the DM. This is at the far end of the spectrum in terms of verbosity, and unsurprising to anyone familiar with Gygax's work. It's also arguably not a bad thing, considering B2 was aimed at beginner DMs. Ratcatchers, on the other hand, sits at odds to its predecessor, inviting experienced GMs to porte over and interpret its contents at will. Terse descriptions let you discover the shape, sounds, smells, and atmosphere of Bruised Apple Lane slowly, with each passing entry. As I read through, I was dogged by questions like

• is this Lane still inhabited by any humans?
• are the lair entrances easily visible from the street?
• are the lairs underground or at stree-level?

I found that my picture of what the Lane actually looked like to a visitor did not fully coagulate until literally the last lines of the module. I ended up making a little overland map to cement my understanding and facilitate description to the players:

I also surmised that while the original Caves had you entering at the bottom of a ravine, with farther-back lairs being at higher altitudes, ratcatchers inverts the altitudes of the originals, with more advanced lairs being deeper down in the Middens. Importantly, I think it could work either way. There's a difference between a module that is simply unclear and one that asks you to interpret it; ratcatchers, I think, is the latter. I decided early on that the altitudes were inverted and was pleased to find that the ruling could be consistently applied across the rest of the map.

My (Dyson Logos') map of the Caves of Chaos, colour-coded by altitude.

To be clear: I think the module is good. The prep work required amounted to less than 3 hours and I enjoyed doing it. Chew your food, etc. etc.

Now for the play report!

Characters:

• John Smiff, literate(just good at guessing words), 'ard as Nails
• Mike the Mug, literate(reads using his tongue), got the morbs
• Mickey Splinters, illiterate, venomous prick

Three new recruits gather in the Ratcatcher's Guild tavern, down at the civilized end of Knight's Orchard Lane. Mickey is already 2s in debt from buying his starting equipment. They resolve to head down Bruised Apple Lane in search of ratman tails, which fetch a shilling each. Ole Blind Larry, a veteran, overhears them and shares what his cousin, a half-ratman, heard: a new, scary gang of ratmen led by a Big Cheese called Hotworms has moved into the northwestern end of Bruised Apple Lane, and they've kidnapped the local councilman, Cordol Orq.

John invites Ole Blind Larry out for a smoke and promptly shanks him to death, looting a few shillings before hiding him under rubbish in an alley.

The gang set off, and arrive in the Lane just after sundown. It's dark and smells like shit. They can just make out heavy foot-traffic in the mud outside several different ruined buildings. John pulls some broken lockpicks out of his pocket and tosses them at the nearest building entrance, a clapped out barn to the north. Eight shadowy, squeaking figures armed jump at the noise, but disperse when they find nothing at its source.

Presuming the coast to now be clear, they wander into the barn. Almost immediately they are surprised by 6 ratman guards. A Molotov shatters the reigning darkness; John is knocked out by the blast. So is Mike, but he also accumulates 10 years' worth of blacklung in a few seconds from inhaling superheated Molotov fumes¹. Mickey fails to speedily disguise himself as a Ratman with makeup, and is disarmed and knocked out by the Ratman guards.

They awaken in the chamber of Reddy the Blacksmith, the Big Cheese of the Ratman Warren they wandered into. He interrogates them. On learning that they seek Hotworms' Warren and the kidnapped councilman, Reddy grows irate, claiming Hotworms is getting too uppity and bringing disruptive morons like John, Mike, and Mickey to the Lane. Reddy presses them into his service. Their task is to either neutralize Hotworms or free the Councilman in order to lower the level of scrutiny on Bruised Apple Lane. Reddy will keep the severely crippled Mike the Mug as a hostage, and sends his most human-like son, Steve-O along to keep an eye on them while they carry out their mission².

On leaving the Warren, they decide to retreat to the Guild tavern for a day to recoup. Steve-O lets John cut his tail off so he can pass as a human more easily. The red stain from his wound is inconsequential; bleeding copiously out of your rear end is a fairly normal occurence in the Smoke.

They find the Ratcatcher's Guild in the middle of a wake for Ole Blind Larry, whose body was discovered that day in a nearby alley. The party all decide to spend the night Carousing in a celebration of Larry's life.

The morning after, Steve-O wakes up nearly a pound in debt and with the worst hangover of his life. Mickey wakes up also nearly a pound in debt, and in bed with a nun named Chastity who has given up her vows to be with him forever. She excitedly shows off the light patch on her finger where the ring used to be that betrothed her to the Hanged Martyr; flung last night into the river at Mickey's behest.

Being the venomous prick he is, Mickey comes up with a plan to dress Chastity in nob's frippery and exchange her to Hotworms for the Councilman, under the pretense that she is actually a Princess of the Country's royal family. With a bit of cajoling and reassurance that they won't let the Ratmen actually hurt her, she agrees.

The party return to Bruised Apple Lane³ and head straight to Hotworms' warren. They knock on the rotted iron sluice-gate at the entrance, and attract the attention of 3 tall, strong Ratmen. Definitely of a finer pedigree than Steve-O and his ilk. The ratman guards agree to take them and their 'prisoner' to see Hotworms and are in the midst of an argument about leaving their weapons by the door when 4 Agents of the Church are spotted coming up the Lane⁴. The guards distracted by this development, John and Steve-O manage to sequester their weapons about their persons.

Hotworms is a freakishly huge Ratman with an equally massive spouse. In his stately chamber, the Ratcatchers present Chastity and ask for the Councilman Cordol Orq. He remains skeptical of this deal until the clangor of battle drifts down from the warren's entrance as the Agents of the Church clash with the Ratman guards. The ratcatchers quickly convince Hotworms that the Agents must be here for Orq, and he can end this trouble and potentially net a greater ransom by swapping Orq for the 'Princess'(Chastity in Nob's clothes).

Hotworms rashly agrees to this⁵ and takes them to the prison cells, where they exchange Chastity for the emaciated Councilman before being hurried out of the Warren and told 'never to come back'.

The Ratcatchers take Orq back to his manner, where he gratefully lavishes them with 12L worth of paintings, books, scrolls, and jewellery. They manage to fence it all for 6L total; with their newfound riches they pay off their bar tabs, buy a dog, and begin to plan for their next escapade.

Oh, and they forgot to return to Reddy the Blacksmith's to collect Mike the Mug. The poor bastard is never seen again.

#swyvers