Tim Matheson
Joe Hardy
Acting
Richard Gates
Frank Hardy
Acting
Jan-Michael Vincent
Tony Prito (as Mike Vincent)
Acting
Portia Nelson
Aunt Gertrude Hardy
Acting
Ricky Kelman
Biff Hooper
Acting
Richard Anderson
Fenton Hardy
Acting
Edward Andrews
Dr Montrose
Acting
James Shigeta
George Ti Ming
Acting
Teri Garr
Susie
Acting