Red Sun Rogue — Taylor Zajonc

As an unknown enemy wreaks havoc in the South China Sea, a renegade submarine captain untangles a deadly conspiracy rooted in lost WWII technology.
 
Salvage diverâ€"turnedâ€"submarine captain Jonah Blackwell and his crew are on a covert mission of mercy, spiriting refugees out of North Korea as a hundred-year winter ravages the Pacific. Hunted by the Japanese fleet and forced to surrender, Jonah and his crew must race against time in an adventure spanning the irradiated waters of Fukushima, flood-beset Tokyo, and the crumbling tropical remains of a secret research facility. At the center of it all is an enigmatic Japanese technology cult with roots in the clandestine weapons program of the Second World War -- a cult that has waited seventy years to strike its final blow.