1894 Wigan. Miss Dorothea Gadsworth is interviewed for a teaching vacancy at George Street Elementary but is ultimately dismissed as a candidate. The following Monday morning her body is discovered in a locked classroom with a note by her side. DS Michael Brennan is called in to investigate what appears to be a straightforward suicide but his instincts tell him there is more to this case than meets the eye. With the door locked from the inside staff members with plenty to hide and a student missing from the school DS Brennan aided by the scowling Constable Jaggery wrestles with one of his most intricate investigations yet.