At the northernmost edge of mainland Scotland, a spectacle unfolds – Orca Watch – a chance to catch a glimpse of one of our most awe-inspiring cetaceans. At survey sites dotted along the Caithness coast near John O'Groats, volunteers assemble for an annual nine-day survey to document these creatures, and this year, Hamza is joining them. While he scans the horizon for tell-tale dorsal fins, Hamza learns how citizen science is transforming what we know about one of the ocean's most intelligent and elusive predators. ‘People power' is the mantra of Orca Watch – and as Hamza makes his odyssey along the coast, he joins other people dedicating their lives to nature and the environment here: the teenager championing an endangered butterfly; the volunteers with a passion for their local beaches; and the man who created a haven for terns in his back garden