From: Elementary ep. 3.12
Event (also characters): Kitty Winter, in revenge for Del Gruner’s brutal abuse of her, throws a corrosive substance into his face, maiming him.
Reference: Actually the Winter revenge / Gruner-as-villain plot begins in the Elementary ep of the same name as its source material: “The Illustrious Client.” There’s even a character named de Merville, who is a victim of Gruner’s barbarous villainy, disguised under a smooth, charming facade. In “Illustrious,” Baron Adelbert Gruner is going to marry Violet de Merville, and an illustrious unnamed client, a friend of the de Mervilles, asks for Holmes’ help in stopping such a thing from occurring, as Gruner is a notorious “ruiner of women.” Problem is, there isn’t any concrete evidence against him, so it’s not like Holmes can easily go arrest him. De Merville won’t believe Holmes or anyone else that Gruner is anything but fully reformed, and even when confronted with Kitty Winter (one of Gruner’s ruined women), she remains confident she has changed Gruner into a contrite saint. Holmes’ (and Winter’s) intense frustration at her naivete is a fantastic scene in the story, btw. Gruner’s undoing would be a book of details he has kept of his victims–Winter has seen it, and knows this is the only thing that will put him away. Holmes manages to abstract the book, but Winter exacts her own revenge without Holmes’ knowledge of her plan: she throws vitriol in Gruner’s face.