Antonia Quirke goes behind the scenes of Bookish, the murder mystery series written by Matthew Sweet and Mark Gatiss, who plays an amateur detective and bookshop owner called Book. Antonia hears from Matthew as he works on the script, crafting a cliff-hanger and deciding just how many red herrings there should be in one episode. He reveals the secrets of his working relationship with Mark, and we join them as they travel to their place of work, a film studio in Belgium, where they discuss which character they are going to murder that day - and how the crime will be committed. Clue: it involves a box of chocolates.When it comes to murder mysteries, Mark has form. He is the co-creator of the hit TV series Sherlock, where he plays Holmes’ brother Mycroft. He has also starred in Game of Thrones, Dr Who and cult comedy series The League of Gentlemen, which he also co-wrote. Matthew Sweet is a broadcaster and expert in Victorian literature, and author of Shepperton Babylon, a best-selling book about the darker sides of British cinema. The pair have been friends for more than a decade, and Bookish is the first TV series they have written together.