The end of Bookish season 1 revealed a new mystery for Gabriel Book and his protégé Jack, that being what happened to Jack's father, Felix.
Felix, a German, had been in a relationship with Book before the war, but Book didn't know what had happened to him since they parted ways. At the end of the season, as he and Jack reunited following an argument, they decided to investigate.
Now, ahead of season 2 debuting, Mark Gatiss has revealed that answers to that mystery are coming, as the third story of the new run will see Book and Jack travelling to Germany to find out the truth.
Speaking with Radio Times, Gatiss said that season 2 is "more ambitious" than the first, adding: "Inevitably we're finding our feet with the first series, and it was deliberately sort of concentrated around Archangel Lane, so that we got to know the precinct and the people and the newcomers, like Jack."
He continued: "And then we moved in the third story, the season finale of six episodes, was in the hotel, a slightly larger environment.
"This year, I think the whole thing just has a slightly broader canvas, and then in episodes five and six we go to Germany, so it does actually open out a bit more. And overall, I think emotionally it's more intriguing. Some of the secrets are unlocked, and some things are answered."
Discussing details of each of the three stories this time around, Gatiss said: "The first one is called Memento Mori, and it's about spiritualism. Jason Watkins plays Harold Sneed, who is a corrupt medium – of course he's corrupt, they all are – and there's a murder during a seance.
"The second one is called Dead Man's Whistle, and is set in the world of off Savile Row tailoring. It's about a suit, Jack's new suit. And the third one is called Killer Nacht, and it's a Christmas story set in Germany, where we go back and find out exactly what happened to Felix."
Meanwhile, when speaking about how Book and Jack's dynamic evolves in season 2, Jack star Connor Finch said: "The two of them have this common meeting place of both caring very deeply about Felix.
"Jack obviously wants to find out as much as he can from Book about him, and Jack, I think, finally finds that in, to sort of find out what did happen there. And so the two of them start working together because they've both got the same interests at heart."
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Along with Gatiss and Finch, season 2 of the period detective drama will see the return of Polly Walker as Book's wife Trottie, Elliot Levey as Inspector Bliss, Blake Harrison as Sergeant Morris and Buket Kömür as the young orphan Nora who, like Jack, helps Book on cases.
Bookish season 2 starts at 8pm on Wednesday 26 August on U&Alibi.
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