Nick investigates two mysterious barn fires that have happened recently. A young woman is also assaulted in a barn by her new boyfriend. The woman is persuaded by her friend, Sandra Murry (Alan Maskell's girlfriend) to report him to the police. It turns out that the woman's boyfriend is also the arsonist responsible for the barn fires. Meanwhile a local woman's horse keeps escaping from it's field and Nick is concerned that it will cause an accident. Kate has another argument with Ferrenby when she puts the unmarried Sandra Murry in touch with the family planning Clinic over birth control. And Greengrass gives Nick a tip-off about a poaching gang and when to catch them. The police organize an operation to catch the poachers, they catch a couple, only later to hear from Lord Ashfordly that a bigger gang cleared the river of fish further along.