Fantasy novel where a pair of sisters, trying to evade a loveless arranged marriage by their father, wind up in a deadly magical game

Question

I think I read this about four years ago (about 2016), although I didn't actually make my way to the end of the book. I think I acquired it as either an eBook or audio book from the library. The setting was vaguely Renaissance, I think, maybe tending toward the Victorian era. The chief protagonist was a female. Her mother was dead. Her father was a merchant who was arranging a loveless marriage for her for the purpose of alliances. She and her sister plot to escape, and somehow wind up snagging invitations (tickets?) for an event sponsored by a mysterious and somewhat malevolent (maybe only in people's minds) man. They sneak out in the middle of the night and attend the event, only to find that it's a deadly game where there can only be one winner who gains a significant boon. The sisters are soon separated. I think the protagonist happens upon an urchin in the streets who offers them more advice than they've earned, with that leading to them being in a hotel where the protagonist encounters her sister (or at that point, she thinks she's encountered her sister) who has somehow been consumed by darkness, which takes the form of a black stain on her.

There was a bit of a motif going on of locations hidden in plain sight, with the hotel in question being accessed by such a portal, with it all being part of the game.

Answer 1

Found it (and verified it was in my read history once I could search for the title). It's Caraval by Stephanie Garber, first book of the series by the same name.

Scarlett Dragna has never left the tiny island where she and her sister, Tella, live with their powerful, and cruel, father. Now Scarlett’s father has arranged a marriage for her, and Scarlett thinks her dreams of seeing Caraval—the faraway, once-a-year performance where the audience participates in the show—are over.

But this year, Scarlett’s long-dreamt-of invitation finally arrives. With the help of a mysterious sailor, Tella whisks Scarlett away to the show. Only, as soon as they arrive, Tella is kidnapped by Caraval’s mastermind organizer, Legend. It turns out that this season’s Caraval revolves around Tella, and whoever finds her first is the winner.

Scarlett has been told that everything that happens during Caraval is only an elaborate performance. Nevertheless she becomes enmeshed in a game of love, heartbreak, and magic.

Found with a search for fantasy novel two sisters arranged marriage deadly game