Kurt Ingston, a rich recluse, invites the doctors who left him a hopeless cripple to his desolate mansion in the swamps as one by one they meet horrible deaths.
| Actor | Role |
|---|---|
 Bela LugosiRolf | Rolf |
 Lionel AtwillDr. King | Dr. King |
 Leif EricksonLaurie | Laurie |
 Irene HerveyDr. Lynne Harper | Dr. Lynne Harper |
 Ralph MorganKurt Ingston | Kurt Ingston |
 Don PorterDick Baldwin | Dick Baldwin |
 Nils AstherAgor Singh | Agor Singh |
 Fay HelmMargaret Ingston | Margaret Ingston |
 Frank ReicherDr. Timmons | Dr. Timmons |
 Doris LloydSarah Judd | Sarah Judd |
 Francis PierlotDr. Phipps | Dr. Phipps |
 Robert HomansCaptain "Cap" Beggs | Captain "Cap" Beggs |
 Janet ShawMillie Carson | Millie Carson |
 Eddy WallerJeb Harmon | Jeb Harmon |
 Cyril DelevantiTorque | Torque |