One month ago, heavily armed militiamen who support the Islamic State (IS) militant group walked into the Somali town of Qandala and seized it without opposition. The town on the Red Sea became the first piece of land controlled by pro-IS forces in Somalia. Qandala emptied out quickly, its several thousand residents fleeing in small groups by car and on foot. But one man tried to stay put, to protect the buildings he considers a treasure: the town's old fish processing plant. His holdout ended Wednesday, when relatives evacuated...