He recently purchased 387 acres on one of the San Juan Islands that is the site of Camp Nor'Wester, a venerated children's summer retreat.
He did not buy any land on any of the San Juan Islands.  
mnli hypothesis: He did not buy any land on any of the San Juan Islands.   premise: He recently purchased 387 acres on one of the San Juan Islands that is the site of Camp Nor'Wester, a venerated children's summer retreat.