The mystery of Bratten’s cold-water corals sets the stage as marine biologist Rhian Waller takes us deep into this remote, protected marine area in the Skagerrak. Aboard R/V Skagerak, she and her team study coral communities thriving hundreds of metres below the surface. Rhian reveals what it’s like to conduct science in these extreme environments: the methods they rely on, the technology they test, and the key questions that keep science in motion. During one of the deep-sea remotely operated vehicle (ROV) dives, something unexpected happens — something with fins. A curious fish makes a move that brings the entire operation to an abrupt halt…