The series will follow Gabriel Book (Gatiss), an “erudite and unconventional” sleuth who cracks mysterious cases from his antiquated bookshop, using the thousands of books that line his shelves to provide him with the knowledge that he needs. Around him are a gathering of “loveable, damaged misfits who he informally protects, cajoles and mentors.”

Detective Hannah Laing, who joins forces with maverick detective Billy Murdoch in a desperate bid to protect her son Christian.