Successful Japanese attacks on key U.S. positions stir Sub-Mariner to action, and he discovers that Japanese agents are sneaking out of American concentration camps into specially built underground tunnels that lead to those key sites.; The Sub-Mariner discovers the Japanese Naval forces using a cleverly disguised and phoney Japanese ship as an American boat to unsuspectingly join American convoys at sea in order to sustain damage to U.S. ships.; The Angel battles an enemy submarine and its crew who are atempting to steal important U.S. documents, not knowing that the Americans already have photostatic copies of them!