A summary is presented of a second multi-club expedition to the Kameno-More region, ‘Sea of Rock’, of Montenegro to continue exploration of Pištet 4 and resolve questions that remained from the 2009 expedition. In 2009 a short, muddy pitch at the base of impressive mud banks approximately 20 m high marked the limit of exploration although a large chamber appeared visible ahead. The 2010 expedition successfully reached that chamber, which mostly comprised a significant sand dune approximately 50 m x 20 m in a large collecting chamber with a side stream passage leading to three pitches and a second smaller sand dune chamber ending in a sump.