This prequel is set 15 years before "A Plague Tale: Requiem/Innocence"
The game starts with the player controlling young Sofia at a nunnery, where she's injected with a substance: the Macula, which we learn Hugo has in the first 2 games.
A heist goes wrong when Sofia learns someone snitched on them. Later in the game, you learn the traitor was one of our own. They surprise Leni and Sofi while solving a puzzle. Sofia encounters the creature she saw in her nightmares after the betrayal. I died so many times during the creature's sections.
The game has no rats but a more dangerous creature and petrifies anyone it catches, and Sofia must find a way to stop it before it takes more lives. The creature made me owe the rats an apology.
Later, when Sofi meets the one guiding her in spirit, this reminded me of Amicia and Hugo's story. I don't want to give too much away.