The Hardys purchase a Chinese junk named the Hai Hau to ferry passengers to Rocky Isle and make some extra money. Four mysterious men also are interested in the boat because of treasure hidden inside the Hai Hau. The Hai Hau is a stolen ship from Hong Kong. The other of the Hardy's friends including Chet Morton and Sam Radley also join the mystery. Their Chinese-America friend, Jim Foy also lends a hand to them. The man, George Ti-Ming, is a private detective who helps his friend in Hong Kong to find his missing ship. Chin Gok and Mr. Montrose are very interested in the junk because they think that the junk has a treasure. Finally, the Hardys solve the mystery and share their rewards with their friends. Chin Gok, Mr. Montrose and the two phony coastguard members are caught by the Bayport Police Department Chief, Police Chief Colig. - Wikipedia.