White-hat assassin siblings have to defend the realm. It’s a bit generic. Good parts: the role of the protagonist as defensive poison expert (unusual and refreshing), and a well-handled siege story. The truly stand-out part of the story was starting with the narrator highlighting the wonderful high-culture city they live in, and then pivoting over time to show the rotting foundations the realm is built on. Well-done, though having only the perspective of the whiny aristocracy took some getting used to.
Not interesting enough to continue.