"The Coming of...Sub-Mariner!"
Chapter 1, "On the Trail of the Torch!"
Chapter 2, "Enter the Sub-Mariner!"
Chapter 3, "Let the World Beware!"
Chapter 4, "Sub-Mariner's Revenge!"
Chapter 5, "Return to the Deep!"
The Human Torch has quit the Fantastic Four, and while the team searches for him, he hides in the Bowery, a haven for the down-and-out. He reads a 1940's magazine about the exploits of the Sub-Mariner and meets an amnesiac homeless man with amazing strength.
Johnny recognizes him and restores his memory by dropping him in the sea. Namor returns to Atlantis to find it destroyed by mankind's nuclear waste, and vows revenge on all surface dwellers. Johnny summons the team, while Namor summons the sea monster Giganto.
The team defeats this first threat, but Namor has a sea full of monsters who will respond to the call of his trumpet. When he sees Sue Storm, though, Namor falls in love. Sue offers to be his bride to save the surface world, but the Torch ends the threat before things go any further.
First Silver Age appearance of the Sub-Mariner.