Holmes and Watson must solve the bizarre murder of four solicitors stabbed in the back. The case involves Moriarty, Fu Manchu and an ancient Chinese custom. Meanwhile, a rattlesnake is killing off the members of a rich family.
| Actor | Role |
|---|---|
 John CleeseSherlock Holmes | Sherlock Holmes |
 William RushtonDr. Watson | Dr. Watson |
 Bill MaynardFrank Potter | Frank Potter |
 Josephine TewsonLady Cynthia | Lady Cynthia |
 Norman BirdInspector Street | Inspector Street |
 Larry MartynFu Manchu | Fu Manchu |
 Michael KnowlesRupert | Rupert |
 Frank MuirSelf | Self |
 Dawn AddamsSelf | Self |
 Ivor SalterAirport Loader | Airport Loader |
| RRosemary LordMabel | Mabel |
 Chic MurrayConstable | Constable |