We have a lot of hypotheses about why we got such a nigredo-laden book in Strike 6.  They are:

• 5-6 flip: which supposes that Troubled Blood was originally planned as Book 6, and The Ink Black Heart as Book 5.
• The Pentagram model: which has the first five books completing the alchemical cycle and the start of a new one in Book 6.
• The Extended Playlist model: Proposed recently by Kathleen, it suggests Galbraith is splitting the last 2, or possibly 3,  books of the 7-part series into two parts. Under this model, The Ink Black Heart would be either part 6a or 5b.

I’m going to outline some of the evidence I see for 5-6 Flip based on one audiobook listen of IBH. As a refresher, recall that this model predicts 1) Career of Evil parallels, instead of or alongside parallels to The Silkworm 2) Order of the Phoenix parallels, instead or alongside those to Half-Blood Prince and 3) nigredo elements, instead or alongside albedo. Interestingly, though, one of the strongest pieces of evidence is none of these, but rather timeline- and calendar-based.

One thing has always puzzled me.  Lethal White ended in mid-September 2012.  Troubled Blood began in August 2013, almost a full year later. This was the second year-long time jump in the series. There were two good reasons for the year-long jump in the middle of LW:  1) Book 4 absolutely had to be set in the 2012 Olympics and 2) no one wanted to read about a full year of Robin trying to make herself love the Flobberworm, develop panic attacks and feel emotionally distant from Strike.

But why jump a full year between LW and TB? It would have been awesome to see Robin’s early days with Max (and Wolfgang! Sniff!), the curry nights with Nick and Ilsa, Robin’s friendship with them developing (and the dirt they dished on Charlotte), the start of the match-making attempts and the series of incompetent temps that culminated in the the decision to hire Pat. OK, we’d have to see the Flobberworm be a jerk for a year, but the rest would be worth that. Instead, that is all explained after the fact. Obviously, the historical floods of 2014 were important to the story, but as has been stated multiple times, you expect lots of rain in albedo, not nigredo books. Why not tell the nigredo story in that missing year and save the floods for albedo?

Second, I can definitely see the Ink Black Heart cartoon as a “text-within-a-text” as stated in Beatrice Grove’s excellent prediction post. But, to me, it doesn’t fit as well as Talbot’s True Book as an analog to either Bombyx Mori, or the Prince’s doctored text. First, those were all actual books. Second, our heroes didn’t wind up actually reading scripts or viewing the cartoon in search of clues to the killer; they instead had to search Twitter and chat rooms for what the fans were saying about the show. That gave it a very different feel to me, and had them examining many different people’s words and the social interactions embedded within the conversations, not the solo narrative of the text. The only person to seriously watch the cartoon was Robin, when she was studying for her moderator’s test, and she didn’t even get to take that.