Ship-girl Stories

It was the year 20XX, and in a parallel world where KANSENs are made into Ship Boys than Ship Girls. Peace has reigned after the World Wars and First Siren War in the early 21st Century. But peace doesn't last forever as an old enemy resurfaces and attacked the world, once the initial assault was done and repelled? it was time for a counter attack where a team of KANSENs are to head into a portal in the Pacific to see where it leads to, but knowing the fate of the entire world is on their hands? They are going to risk everything and find out who or what's causing this resurgence.