High school student Asuna struggles to survive with a young swordsman after its revealed that she is trapped inside the game of Sword Art Online, where if your HP drops to zero, your brain will be destroyed in real life.

Sword Art Online: Progressive - Aria of a Starless Night

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…