In the new adventures folder for the Witcher 1 I have a file called 'kniga_2.adv' which starts with a cutscene where I can only hear Geralt speaking in Polish presumably, there are no subtiles; it just says EXTRA. There are also a lady and a gentleman (the man is using the Jacques de Aldersberg skin) but they don't say anything.
Any ideas what this adventure is and what it's about?