Plot summary

Shortly after his arrival in United States, a Japanese business tycoon mysteriously disappears. Mr.Hardy, who had been entrusted with the man's security, is baffled and shocked. He feels even worse when the FBI takes him off the case.

However, his sons, Frank and Joe, are there to investigate. A valuable samurai sword, said to have belonged to the missing tycoon's family for generations, is stolen from an auction gallery in New York, and the boys suspect a connection. One clue leads to another, and danger confronts them constantly on their search for the solution to the puzzle.

Who are their enemies? Did the criminals kidnap the missing businessman, or did he hide of his own volition? What is the secret of the stolen samurai sword?

• Publication date: 1979