Over a month has passed since 10,000 users were trapped inside the "Sword Art Online" world. Asuna, who cleared the first floor of the floating iron castle of Aincrad, joined up with Kirito and continued her journey to reach the top floor. With the support of female Information Broker Argo, clearing the floors seemed to be progressing smoothly, but conflict erupts between two major guilds who should be working together – the top player groups ALS (the Aincrad Liberation Squad) and DKB (the Dragon Knights Brigade). And meanwhile, behind the scenes exists a mysterious figure pulling the strings…
One month after Kayaba Akihiko's game of death began, the death toll continues to rise, two thousand players having already lost their lives to the ultra-difficult VRMMO world of Sword Art Online. On the day of the strategy meeting to plan out the first-floor boss battle, Kirito, a solo player who vows to fight alone to get stronger, runs into a rare, high-level female player. She gracefully dispatches powerful monsters with a single rapier that flashes like a shooting star in the night...
Living by the sea, protecting the sea, and journeying across the sea…They’re the BLUE MERMAIDS! Because of a shift in tectonic plates around 100 years ago, Japan lost much of its area to submergence. To preserve Japan’s territories, Coastal Cities sprung up, one after the other. Eventually, they became Marine Cities, and along with the expansion of sea-lanes to connect them, the need arose for a sizable staff to protect the seas. At the same time, maritime jobs were becoming more popular among women. Hence, the BLUE MERMAIDS had become every female student’s dream job.