 | Ralph Byrd | ... | Lt. Terry Kent |

| Bela Lugosi | ... | Boroff, alias M.A. Anderson |
 | Maxine Doyle | ... | Jean Norman |
 | Richard Alexander | ... | Thorg |
 | Lee Ford | ... | Snapper McGee |
 | Herbert Rawlinson | ... | Cmdr. Boyle |
 | John Picorri | ... | G.A. Rackerby |
 | Lawrence Grant | ... | Rabinisi (Boroff's spokesman at screening) |
 | Thomas Carr | ... | Ens. Jim Kent |
 | Carleton Young | ... | Henchman Dodds [Ch. 4] |
 | Allen Connor | ... | Dick Norman |
 | George Chesebro | ... | L.H. DeGado - Chief Thug |
 | Ranny Weeks | ... | Wies - Ambulance Orderly thug |
| rest of cast listed alphabetically: |
 | Roy Barcroft | ... | Goebel, Henchman [Chs. 2, 10] (uncredited) |
 | Richard Beach | ... | Seaman (uncredited) |
 | Earle D. Bunn | ... | Kelp Plant Heavy 1 [Chs. 8-9] (uncredited) |
 | Yakima Canutt | ... | Seaman (uncredited) |
 | Ed Cassidy | ... | Patrol Boat Capt. Johnson [Chs. 1-3, 5, 12] (uncredited) |
 | Jack Clifford | ... | Carver (uncredited) |
 | Baldwin Cooke | ... | Seaman (uncredited) |
 | Floyd Criswell | ... | Motorcycle Heavy [Ch. 8] (uncredited) |
 | Jack Daley | ... | Captain of the S.S. 'Carfax' [Ch. 1] (uncredited) |
 | Leon Davidson | ... | Seaman (uncredited) |
 | Forrest Dillon | ... | Sea Wolf Thug [Ch. 7] (uncredited) |
 | Lester Dorr | ... | Hospital Radium-Tech [Ch. 11] (uncredited) |
 | Curley Dresden | ... | Dock Heavy 1 [Chs. 6-7, 10] (uncredited) |
 | Robert Dudley | ... | Pierport Station Agent [Ch. 6] (uncredited) |
 | Norwood Edwards | ... | Seaman (uncredited) |
 | Frank Ellis | ... | Kelp Plant Worker [Ch. 8] (uncredited) |
 | Frank Fanning | ... | Roadside Police Sergeant [Ch. 3] (uncredited) |
 | Jerry Frank | ... | Sea Wolf Thug [Chs. 3, 5, 7] (uncredited) |
 | Lee Frederick | ... | Citizen [Ch. 3] (uncredited) |
 | Audrey Gaye | ... | Telephone Switchboard Supervisor [Ch. 2] (uncredited) |
 | Joseph W. Girard | ... | Cmdr. Green [Ch. 1] (uncredited) |
 | Kit Guard | ... | Kelp Plant Heavy 2 [Chs. 8-9] (uncredited) |
 | Henry Hale | ... | Krohn - Morovanian Scientist (uncredited) |
 | Jack Ingram | ... | Seaman [Chs. 2-3, 6-7] (uncredited) |
 | Warren Jackson | ... | Boat Heavy #4 [Ch. 5] (uncredited) |
 | Payne B. Johnson | ... | Boy in lifeboat (uncredited) |
 | Jerry Larkin | ... | Henchman (uncredited) |
 | Rex Lease | ... | Coast Guard Orderly [Chs. 1, 3] (uncredited) |
 | Alexander Leftwich | ... | Froman, Morovanian emissary [Ch. 1] (uncredited) |
 | Jack Long | ... | Seaman (uncredited) |
 | Joseph P. Mack | ... | Captain of the S.S. 'Adamic' [Chs. 5-6] (uncredited) |
 | Teddy Mangean | ... | Seaman (uncredited) |
 | Gene Marvey | ... | Blake (uncredited) |
 | Frankie Marvin | ... | Sniper [Ch. 7] (uncredited) |
 | Frank Meredith | ... | Policeman [Ch. 6] (uncredited) |
 | James Millican | ... | Dock Heavy 4 [Chs. 6-7, 10] (uncredited) |
 | Pat Mitchell | ... | Radioman (uncredited) |
 | King Mojave | ... | Ambulance Driver-Thug [Chs. 3-4] (uncredited) |
 | Edwin Mordant | ... | Dr. Meade [Chs. 6, 11] (uncredited) |
 | Michael Morgan | ... | Coast Guardsman Moore [Chs. 3, 11-12] (uncredited) |
 | Henry Morris | ... | Dock Heavy 2 [Chs. 6-7, 10] (uncredited) |
 | Charles Murphy | ... | S. S. 'Adamic' Mate [Chs. 5-6] (uncredited) |
 | John Mustin | ... | Policeman (uncredited) |
 | Henry Otho | ... | Mate on the S.S. 'Carfax' [Ch. 1] (uncredited) |
 | Eddie Phillips | ... | Boat Heavy 1 [Ch. 5] (uncredited) |
 | Loren Riebe | ... | Pete, Thug [Chs. 5, 8] (uncredited) |
 | Vinegar Roan | ... | Dock Heavy 3 [Ch. 6-7, 10] (uncredited) |
 | Jack Roberts | ... | Jones - Racherby's Lab Assistant [Ch. 2] (uncredited) |
 | Buddy Roosevelt | ... | Patrol Boat Lt. Scott (uncredited) |
 | Dick Scott | ... | Gang Launch Pilot [Ch. 1] (uncredited) |
 | Reed Sheffield | ... | Thug Loading Launch [Ch. 11] (uncredited) |
 | Dick Sheldon | ... | Ambulance Attendant-Thug [Chs. 3-4] (uncredited) |
 | Harry Strang | ... | Phone Company Code Expert [Ch. 2] (uncredited) |
 | Duke Taylor | ... | Loader [Ch. 6] (uncredited) |
 | Tom Ung | ... | Charlie, 'Sea Wolf' Cook [Ch. 7] (uncredited) |
 | Billie Van Every | ... | Telephone Operator [Ch. 2] (uncredited) |
 | Robert Walker | ... | Henchman Black [Chs. 6-7, 10] (uncredited) |
 | Frank Wayne | ... | Henchman Payne [Chs. 3, 5, 7-8, 10-11] (uncredited) |
 | Herbert Weber | ... | Belden, Cargo Clerk-Thug [Ch. 5] (uncredited) |

| Robert J. Wilke | ... | Seaman (uncredited) |
 | Robert Williams | ... | Sloan, Henchman [Ch. 8] (uncredited) |
 | Roger Williams | ... | Black, a Thug [Chs. 6-7, 10] (uncredited) |
 | Dan Wolheim | ... | Sea Wolf Captain Slauson [Ch. 7] (uncredited) |
 | Duke York | ... | Sea Heavy #1 [Ch. 5] (uncredited) |
Boroff, a munitions expert, has just perfected a disintegrating gas which he plans to sell to any nation that will meet his price. Despite being a wanted man across the world, Boroff smuggles himself aboard the SS Carfax to ship a load of arnotite to Morovania, who plans to use the disintegrating gas. The Carfax is wrecked at sea and is rescued by the Coast Guard led by Lieutenant Terry Kent. Boroff is recognized but manages to escape the Coast Guard, while killing Kent's younger brother Jim. Boroff disguises himself and plans to manufacture the disintegrating gas while evading the watch of Kent and the Coast Guard, who go piece clues together to find Boroff and stop the gas from being made, which also means battling Boroff's lobotomized, hulking servant Thorg. The serial had a great first two chapters and well done ending, but the middle part of the serial was very routine since all of the atmosphere, villainous characterizations, and action packed encounters seemed to be lessened. Richard Alexander must have had a great agent for getting him these memorable serial roles, since Thorg is among his best, where he evokes a lot of sympathy from the audience. Lugosi is fine here as well, but as I said before, he loses his evil touch as the serial progresses. Byrd is somewhat disappointing comparing this to his Dick Tracy roles since his reading of lines doesn't always sound too heroic. Doyle is cute, but no actress, and Ford is annoying as he was in Dick Tracy Returns. Rating, based on serials, 6.