The Hardy Boys become owners of the Chinese junk Hai Hau. They head to New York City and go spelunking to break up a gang of criminals.
Tim Matheson
as Joe Hardy
Richard Gates
as Frank Hardy
Jan-Michael Vincent
as Tony Prito (as Mike Vincent)
Portia Nelson
as Aunt Gertrude Hardy
Ricky Kelman
as Biff Hooper
Richard Anderson
as Fenton Hardy
Edward Andrews
as Dr Montrose
James Shigeta
as George Ti Ming
Teri Garr
as Susie
