Police investigating the disappearance of a popular barman find human remains near Aviemore. In Caithness, cops are shocked to discover tropical animals in a derelict house.

A team of police travel to the Outer Hebrides to search through the snow for a missing 16-year-old. In Shetland, the cops have to deal with Viking revellers and a drunk driver.

Police in Inverness raid a flat and discover a laboratory containing a number of dangerous chemicals and electrical circuitry. They evacuate the area and call in the bomb disposal team.

PC Stephen Cooper co-ordinates a desperate search for two missing hillwalkers in Glencoe, and, in the Cairngorms, cops investigate a suspected shotgun attack on the nest of a protected bird of prey.

On the Isle of Lewis, a police officer confronts an angry fisherman who he suspects has been illegally poaching salmon. In Fort William, police respond to reports that a young woman is attacking a man with a knife.

Armed police target the operations of a violent county lines drug gang in Inverness. And in Glencoe, PC Stephen Cooper has to track down and detain a high-risk missing person.