D.J. Arneson (writer), Ray Bailey (artist), Vic Gorelick (colors)
From Undersea Agent #1 - 14 pages - A dozen military vessels of the West have gone missing. The latest is the USS Gettysburg, an aircraft carrier from which a radio message indicated a poisonous gas had killed the crew. Lt. Jones is seconded to U.N.D.E.R.S.E.A. to investigate.
Here are the pages I have of it.