Trygve Yamamura is a Hawaii born half-Norwegian, half-Japanese private detective who works as a college professor at Berkeley, California. An expert in the field of Japanese Samurai swords and a skilled marshal artist, he presents a great threat to the criminals in San Francisco Bay Area. When a teaching assistant in the Berkeley history department is found murdered, Yamamura's friend Professor Kintyre gets mixed up over his head, and the witty detective gets involved before someone else loses his head.