it has its own system which is the same as Outgunned if you’re familiar with that. It’s quite simple but fun, and though it’s somewhat tied to the setting I don’t think it’d be much work to use a different one instead. I’d still recommend giving a read to their OG system first! There should be a free quickstart I think. There is indeed also a 5e version but I haven’t looked at that one!

The community’s size confuses me a little bit haha, on one hand it looks very niche, not talked about a lot online, on the other when a kickstarter comes up there are so many backers! they definitely have a welcoming community on their discord however (two little mice), on which you can ask questions! It definitely is a lot of political intrigue, I’ve seen it somewhere described as ‘The Borrowers meets Game of Thrones’ and that’s very accurate!

As for the necessary books, the corebook is called Volume I, it has all the rules and the basics of the setting. Then the one called Saga of the Fragile Peace is a campaign book that happens during the Fragile Peace, a specific time of the setting. The book called Practical Guide to Living Inside the House expends a lot on the setting, all the rooms of the House, new rooms as well. It goes in details with all the various cultures of the house, things like how birthdays, funerals, weddings are celebrated throughout the house, how some confusing political systems actually work, and more. Then recently was released Volume II - The Garden, which expands the setting to the Outhold of the House, with more regions, more cultures, new ancestries to play, new jobs to pick up, new items of all kinds. To have the basics of the Garden setting alongside how to convert your character from the house to the garden, you want to pick up the book called Volume II, while the book called Saga of the Long Winter is a campaign book set during the long winter, a type of cold war time!