| 0 | Thunder on the Seas | cover | 1 | pencils: Lou Fine; inks: Lou Fine | Hercules [Joe Hercules] |
| 1 | The Burns Koffin Gang | comic story | 7 | pencils: Dan Zolnerowich; inks: Dan Zolnerowich | Hercules [Joe Hercules]; Burns Koffin (villain, introduction) |
| 2 | Assignment: Spain | comic story | 6 | script: Will Eisner | X-5; Fred Ricks (introduction); The Bothnians (villain, introduction) |
| 3 | The Two Aunt Agathas | comic story | 6 | pencils: John Lindermayer; inks: John Lindermayer | Jack Doe; Jill Doe; "Aunt Agatha" (a female impersonator, villain, introduction) |
| 4 | The Photographer's Murder | comic story | 6 | pencils: Charles Nicholas; inks: Charles Nicholas | The Red Bee |
| 5 | The Dope Pearls | comic story | 7 | script: S. M. Iger; pencils: Alex Blum; inks: Alex Blum | Rod Strange; Douglas Strange; Vera De Vain (villain, introduction); Sari (introduction) |
| 6 | Spies in Puerto Rico | comic story | 6 | script: Klaus Nordling; pencils: Klaus Nordling; inks: Klaus Nordling | Bob Masters; Swab Decker; Luisa (villain, introduction); other spies (villains, introductions) |
| 7 | The Chicago Run | comic story | 5 | pencils: Munson Paddock; inks: Munson Paddock | Casey Jones |
| 8 | The Cat's Ninth Life | text story | 2 | script: Toni Blum (Tony Boon); letters: Typeset | |
| 9 | The Tale of the Ghost Cavaliers | comic story | 5 | pencils: Pierre Winters; inks: Pierre Winters | |
| 10 | Voyage to the Center of the Earth | comic story | 5 | script: Roy Talon; pencils: Henry Kiefer; inks: Henry Kiefer | Blaze Barton; Beatica (Queen of the Jewelled Caves, introduction); The Core-men (villains) |
| 11 | Treasure on Koko's Island | comic story | 2 | script: Sandy Klauz; pencils: George Tuska; inks: George Tuska | Tommy Tinkle |
| 12 | The Savage Land | comic story | 7 | script: S. M. Iger; pencils: Alex Blum; inks: Alex Blum | Neon the Unknown |