Meitantei Conan: Konpeki no Hitsugi (Jolly Roger)

A group of treasure hunters is encountered by Conan and his companions during a vacation on the Pacific island of Koumi. The island is known for a legend about the Seabed Palace, an ancient underwater ruin said to contain the treasure of two historical female pirates, Anne Bonnie and Mary Reed. The visitors sense something unusual about the treasure hunters.