陈三元(滕丽名 饰)自小就受叔叔小生（欧阳震华 饰）影响，大学毕业后便当上了警察，是个陀枪女警。表现出色调到了“扫黄组”，但上司程峰（魏骏杰 饰）一直对她有性别歧视，好胜的她一直争取好表现。期间她认识了当文职的朱素娥（关咏荷 饰），人称娥姐。娥姐原本有一个幸福的家庭，后来离婚了不得不也做一个陀枪女警。
　　接着娥姐也认识了小生，与小生成为了一对斗气冤家，后来竟然变成了情侣。而三元与程峰经过一段相处后互相了解了许多，成为了好朋友。令三元想不到的是自己竟然喜欢上了程峰……

　　本剧讲述以范仁生为首的抢劫集团以打劫大巴士乘客为目标，对社会造成了严重危害，警察进行缉拿劫犯的惊心动魄的故事。

　　陈三元(滕丽名 饰)自小就受叔叔小生（欧阳震华 饰）影响，大学毕业后便当上了警察，是个陀枪女警。表现出色调到了“扫黄组”，但上司程峰（魏骏杰 饰）一直对她有性别歧视，好胜的她一直争取好表现。期间她认识了当文职的朱素娥（关咏荷 饰），人称娥姐。娥姐原本有一个幸福的家庭，后来离婚了不得不也做一个陀枪女警。
　　接着娥姐也认识了小生，与小生成为了一对斗气冤家，后来竟然变成了情侣。而三元与程峰经过一段相处后互相了解了许多，成为了好朋友。令三元想不到的是自己竟然喜欢上了程峰……

　　Morse is taken seriously ill at a museum reception and is hospitalized. In the hospital, Supt. Strange, visits Morse to push him to take early retirement, while Dr. Millicent 'Millie' Van Buren gives him her book on a 140 year-old court case known as the Oxford Canal Murders. The case involved the murder and rape of a young woman, Mrs Joanna Franks, traveling by canal boat from Coventry to London. The case resulted in three boatmen being sentenced to death and two of them hanged. Morse starts to read Millie's book and dreams about it. He soon has a number of problems with the case.
　　Why weren't the three men also charged with theft? Why did Mrs Franks take a boat instead of a train that was much faster and comfortable and only slightly more expensive? Why didn't she abandon the boat after she complained about lewd behavior of the crew at the shipping office in Banbury? Why did she then drink and 'socialise' with the crew? What happened to her 'carpet bag' with which she arrived on the boat but which was not mentioned in the court case, nor was it stored in the archives with her, almost empty, trunk? The trunk was marked with initials of her first husband who had died. How did it happen that her shoes were found on the boat but nobody saw her return to the boat from the forest?
　　PC Adrian Kershaw does some brilliant leg work for Morse. He studied history and has invaluable background knowledge. For instance, he mentions that the boatmen had bad reputation because they worked on Sundays and did not attend church. Later a chapel was built for them in Oxford.
　　The dead woman's clothes and the shoes found on the boat are submitted to modern forensic investigation. The result is that the shoes did not belong to the dead woman found in the water because she was much taller.The shoes were never used in the forest.
　　Only Mrs Franks' husband, Charles Franks, was called to identify the body of the dead woman. He claimed that, while her face was darkened and disfigured, he found a birth mark behind her ear. The prosecutor welcomed that information "that only a husband or a lover would know". The accused were not shown the body. The defense attorney merely claimed that the guilt of the three men was not proved. All three accused claimed to the end that they were innocent. One of them was not executed because he embraced Christianity in prison.
　　Morse instructs Kershaw to investigate if Charles Franks benefited from his wife's death and, indeed, he pocketed 300 pounds insurance money. Case closed: Charles Franks murdered a tall women and dropped her in the canal after meeting Joanna in the forest. If Joanna Franks jumped off the boat at the same time as the dead body hit the water, she swam to the bank and joined her husband. The couple changed their names, in the case of 'Charles Franks' a second time after he 'died' as Joanna's first husband. The fourth boatman, a youngster who was not charged, was probably paid by Joanna to give false testimony.
　　Morse travels to Ireland and has a grave of Joanna's first husband exhumed. The coffin contains bags of sand and some stones.