The county lines drug epidemic has taken further hold in Inverness, bringing increased violence and drug deaths. Residents feel under siege as criminals take advantage of local addicts, using their homes to deal from in exchange for free drugs. After another overdose-linked death, specialist CID officers bust down doors in search of the gangs. Meanwhile, 80 miles to the south, police respond to a phone call from walkers who have spotted a body in a river upstream from Loch Arkaig. Specialist teams are deployed to the scene, but the river is in spate and it is impossible to search the area safely. The team find items of clothing which identify the body as a solo hillwalker from Germany. During a break in the weather, the police and rescue teams race against time to find the body and return him to his family before he is lost forever in the 100m-deep loch. And in Aviemore, reports of a skier caught in an avalanche raises the alarm.