By the time Marvel Mystery Comics #5 came out, around the beginning of 1940, publisher Martin Goodman had seen enough profit on the first issue or so that he had already launched a second Timely title: Daring Mystery Comics.
Johnson, a friend of the Human Torch, now known as Mr. Jim Hamond, shows the latter his hobby - short wave radio
The Human Torch [Jim Hamond]; Johnson; Tom; Blake (villain introduction, death); Hank (villain, introduction, death)
A medical emergency and crisis in the city of Orton during a blizzard forces the Torch to make a trip to that town with a plane full of medical supplies. Unfortunately, the plane crash lands and the supplies are stolen by a couple of escaped convicts.
Namor, after successfully ending the mine and sub menace in the Atlantic, briefly visits home, then heads back to America to help out with ending non-war related crime. But upon his arrival, he is immediately taken prisoner until Betty Dean convinces the authorities to release him to deal with criminals that have flooded the city's subway system.
Calling operatives 1 and 4 - report to headquarters at once!
Electro; Dr. Phil Zog; King Sangor; Operative #1; Bill (Operative #4); Kalph Belgri (villain, introduction, death)
Professor Zog informs Operatives #1 and #4 that he is going to dispatch Electro and them to the Republic of Molivia, which has been attacked and invaded by the dictator armies of Kalph Belgri, who seeks to control that nation.
The Sub-Mariner [Prince Namor]; Betty Dean; Marty (Policeman); Mike (Policeman)
After helping to clear up up the subway disaster, Namor is put on trial for his life and sentenced to death, but is saved by the actions of Betty Dean. However, Namor vows revenge for what has happened to him.
One day, while on a trip through the forest, he heard a peculiar droning sound in the sky.
Ka-Zar [David Rand]; Professor Rice (death); Mara Rice (Professor's daughter); Zar (a lion); Trajah (an elephant); "Red" Skelton (villain, death)
Ka-Zar notes the arrival of a Professor Rice, a botanist who has come to the Belgian Congo to search for certain rare species of plant life. Unfortunately for the good Professor, his pilot is a thief and murderer, who not only intends to blackmail the Professor for $100,000, but also to marry his daughter.
The Human Torch [Jim Hamond]; Jeff (policeman); Frank (policeman); Sub-Mariner [Prince Namor]; Betty Dean
Embittered because the Police Chief believes Torch to be yellow because he failed to bring in the Sub-Mariner, the Torch races off to repair some of the damage Namor caused. He meets up with Betty and together they head for the Empire State Building where the Prince has been spotted, and once again drives Namor away.
The Masked Raider [Jim Gardley]; Mexican Pete (introduction); Brady (villain)
The Raider runs into Mexican Pete, who has attempted to trail the thieves who just robbed a local bank and made off with the savings of the small ranchers. But the Raider smells a rat and that rat is the President of the robbed bank!
Steve runs across a cabin inhabited by two train robbers, but is rendered unconscious. When he awakes, he must discover why they have come to this shack in Silver Mountain and tied him to a cot when there is no silver left in that area.
Drake kills the man who has inherited a gold mine worth far more than he thought because he refuses to use the local natives as slave laborers. The local tribal chief enlists the aid of Ka-Zar to deal with the problem.