This is a below average "whodunit" with the cliche everyone in the living room routine. Charlie Chan is a Secret Service Agent doing government work, and he must find who killed a scientist working on a bomb to defeat German U-boats in World War Two. There is little to recommend with this movie, since the neither the bomb nor the scientist nor the war have much to do with the plot. Charlie Chan fans will most likely find this movie disappointing. Who dunit? Who cares?