Neil takes to the air on an RAAF training mission to seek and destroy submarine invaders. Palaeontologist and explorer Professor Tim Flannery has a close encounter with history as he uncovers an unlikely meeting between two French and English navigators at Encounter Bay. Landscape architect Brendan Moar visits the moody Coorong to remember the ground-breaking Australian film Storm Boy. Neil investigates the quest to preserve Adelaide's mother-ship, freshly saved from Scottish ruin. Marine ecologist Professor Emma Johnston dives deep into the stunning underwater caverns of the Limestone Coast. In Robe, historian Dr Alice Garner gets a taste of how Victoria's gold rush was the making of this coastal town across the border, and Neil examines new archaeological evidence of a wild fur trade that sprung up on remote Kangaroo Island, and its lasting impact on the endangered sea lions of Seal Bay.