Lewis - Dark Matter

When Andrew Crompton, the Master of Gresham College, is found dead at the foot of the University observatory stairs, Lewis and Hathaway get an insight into the hierarchical nature of college life as the net of suspicion is cast from the senior college tutors right down to the head porter. Lewis quizzes senior lecturer Gwen Raeburn about a notebook found at the murder scene and she reveals it belongs to her student Jez Haydock. After checking security records, Hathaway discovers that Jez had accessed the observatory around the time of Crompton's death. Dr Laura Hobson was also at the college rehearsing for a performance with the orchestra of Sir Arnold Raeburn, Gwen's husband. The couple were close friends of Crompton, and Lewis asks Hobson if she can keep an eye on the Raeburns at the next rehearsal. But an astronomical text sends Lewis and Hathaway back to the observatory, where they make the discovery that finally provides the answer to the riddle of Crompton's death.