Enredo

When Lucien is found at Ballarat Observatory standing over a dead body, covered in blood, the investigation quickly turns back onto Blake himself.

Tensions have reached boiling point between Doctor Blake and Major Alderton - Blake now knows Alderton has been using Mei Lin in a psychological game of cat and mouse against him. So when Alderton is found dead at Ballarat Observatory during a once in a century eclipse, and the police learn Blake was at the scene, and fled, the hunt for the killer turns back onto Blake himself.

Blake takes a pistol to the Ballarat observatory on the day of an eclipse to meet Major Alderton. The Major is using Mei Lin to force Blake to return to the army for service in the growing Indo-China war and Blake will not be forced. As the sky darkens during the eclipse Alderton is stabbed in front of Blake, but the murderer is not known. The operator of the Observatory is suspected, as is Blake. Sullivan from the Special Branch of the military arrives to supervise the investigation by the police into Alderton's murder. He is a cocky man, with an almost lunatic grin. Sergeant Robert Hannam was seen entering the observatory and seen leaving it in a green Studebaker by Rose. He is a dangerous hit man for the military, who says he was present in case anything went awry between Alderton and Blake. A sharp instrument is found in Mei Lin's room at the hotel, and Blake is arrested on the evidence of that being the murder weapon. Jean and Mei Lin are visited by Hannam, so they stay at a local hotel for safety. Dr Harvey tells the police that the murder weapon is a finely measured bit of equipment from a complex machine. Blake realises that is the large telescope, which Charlie confirms when he visits Dr Joanna Bainbridge at the observatory. She is rattled as Hannam had been to visit her not long before Charlie arrives. From his cell in Ballarat, Blake works on solving the murder, the simple geometry of the event. Sullivan shows Blake the file former Superintendent Munro kept on him, and then asks Blake how many he killed in his time in Special Branch and how he can be away from that life; Blake names the two men he killed and assures Sullivan that he is happy as a country doctor. Superintendent Carlyle and Sullivan say the next step for Blake is going to Melbourne office of Special Branch; this is a ploy by Blake and Carlyle to flush out the murderer but only they know this. Mei Lin confesses to get Blake released, with true details about how Alderton pursued and threatened her to get to Blake as well how she committed the murder. She is put in the cell and Blake is released. While Hannam visits Blake and Jean at their house, and explains Alderton's mistakes and unreliability, Carlyle shows up at the house. Hannam slips away, and Blake becomes aware that Mei Lin was flushed out with her false confession. They race to the cell, saving her from Sullivan, the murderer of Alderton, who is trying to hang her. Sullivan is arrested. Mei Lin asks Blake how he and Alderton stopped being good friends. The two were in a brutal camp and it broke Alderton's will to live, but Blake kept him alive, and Blake thinks Alderton never forgave him for that. The military police arrive to escort Sullivan away. He in turn is murdered by Hannam. Carlyle pushes Hannam down, until they get him to stop shooting, and arrest him. Carlyle arranges for Mei Lin to meet her family safely in Hong Kong, which she accepts, as it is time to start a new life. When Blake and Jean are finally alone, they kiss.

Blake takes a pistol to the Ballarat observatory on the day of an eclipse to meet Major Alderton. The Major is using Mei Lin to force Blake to return to the army for service in the growing Indo-China war and Blake will not be forced. As the sky darkens during the eclipse Alderton is stabbed in front of Blake, but the murderer is not known. The operator of the Observatory is suspected, as is Blake. Sullivan from the Special Branch of the military arrives to supervise the investigation by the police into Alderton's murder. He is a cocky man, with an almost lunatic grin. Sergeant Robert Hannam was seen entering the observatory and seen leaving it in a green Studebaker by Rose. He is a dangerous hit man for the military, who says he was present in case anything went awry between Alderton and Blake. A sharp instrument is found in Mei Lin's room at the hotel, and Blake is arrested on the evidence of that being the murder weapon. Jean and Mei Lin are visited by Hannam, so they stay at a local hotel for safety. Dr Harvey tells the police that the murder weapon is a finely measured bit of equipment from a complex machine. Blake realises that is the large telescope, which Charlie confirms when he visits Dr Joanna Bainbridge at the observatory. She is rattled as Hannam had been to visit her not long before Charlie arrives. From his cell in Ballarat, Blake works on solving the murder, the simple geometry of the event. Sullivan shows Blake the file former Superintendent Munro kept on him, and then asks Blake how many he killed in his time in Special Branch and how he can be away from that life; Blake names the two men he killed and assures Sullivan that he is happy as a country doctor. Superintendent Carlyle and Sullivan say the next step for Blake is going to Melbourne office of Special Branch; this is a ploy by Blake and Carlyle to flush out the murderer but only they know this. Mei Lin confesses to get Blake released, with true details about how Alderton pursued and threatened her to get to Blake as well how she committed the murder. She is put in the cell and Blake is released. While Hannam visits Blake and Jean at their house, and explains Alderton's mistakes and unreliability, Carlyle shows up at the house. Hannam slips away, and Blake becomes aware that Mei Lin was flushed out with her false confession. They race to the cell, saving her from Sullivan, the murderer of Alderton, who is trying to hang her. Sullivan is arrested. Mei Lin asks Blake how he and Alderton stopped being good friends. The two were in a brutal camp and it broke Alderton's will to live, but Blake kept him alive, and Blake thinks Alderton never forgave him for that. The military police arrive to escort Sullivan away. He in turn is murdered by Hannam. Carlyle pushes Hannam down, until they get him to stop shooting, and arrest him. Carlyle arranges for Mei Lin to meet her family safely in Hong Kong, which she accepts, as it is time to start a new life. When Blake and Jean are finally alone, they kiss.