From 8-24 January 2016 the 5th consecutive Polar Night cruise with RV Helmer Hanssen took place. As in previous years, the cruise took place in Svalbard waters. The scientific program started in Isfjorden before Helmer Hanssen brought us north to Smeerenburgfjorden, Rijpfjorden and close to the ice edge to 81 N. The second leg of the cruise focused as in previous years on investigating processes in Kongsfjorden. We did not encounter any landfast or drift ice during the cruise. This Polar Night cruise was mainly a contribution to two Mare Incognitum projects: Arctic ABC and Marine Night, as well the UiT master course BIO-8510 ARCTOS - Marine ecological research cruise to Svalbard. The scientific program included sampling zooplankton, benthic and fish communities using traditional methods (nets, trawls, grabs and box corer) as well as applying modern technologies such as the Acoustical fish and zooplankton profiler as well as a number of optical methods (Video Plankton Recorder, Laser Optical Plankton Counter, under water bottom camera, ROVs and hyperspectral imaging systems). In addition to the biological program, marine archaeological research was conducted in Isfjorden and Smeerenburg using automated under water vehicles (AUV) and ROVs equipped with imaging systems. We were also very successful in deploying a Jetyak (automated kayak). Equipped with optical and acoustical sensors the Jetyak can do measurements further away from the research vessel thus conducting measurements of light and vertical migrations of zooplankton in areas undisturbed by light emitted from the boat. A lot of great discoveries and new insights into the secrets of the polar night were gained – some of which will appear in media in the weeks to come (see links below), others in scientific journals later in the year or next year. Overall, the cruise was very successful with all planned sampling running smoothly and the weather being cooperative.