内容简介：
There's something weird and mysterious about the robbery, Kennedy. They took the very thing I treasure most of all, an ancient Peruvian dagger. Professor Allan Norton was very much excited as he dropped into Craig's laboratory early that forenoon. Norton, I may say, was one of the younger members of the faculty, like Kennedy. Already, however, he had made for himself a place as one of the foremost of South American explorers and archaeologists. "How they got into the South American section of the Museum, though, I don't understand," he hurried on. "But, once in, that they should take the most valuable relic I brought back with me on this last expedition, I think certainly shows that it was a robbery with a deep-laid, premeditated purpose." "Nothing else is gone?" queried Kennedy.