One year ago, an artificially created species of human-dragon hybrids escaped from Sakai Industries and began to wreak havoc on Stardust City.

After learning that the hybrids, formally known as the Aria, escaped from Sakai Industries, the government demanded the company take responsibility and defend the city from their rampages. Sakai Industries agreed, and the Aria Strike Force was born.

When the Force was first formed, they were hundreds strong--but by its first anniversary, Stella Sakai and Yui Dendrite are the only ones left.

Stella, daughter of the CEO of Sakai Industries, feels deeply responsible for the death of her comrades--especially once she discovers many died protecting her on her mother's orders.

Frustrated by her own weakness, Stella vows to grow stronger--but upon meeting an Aria who seems to control their violent urges, she begins to question her mission—and the person who gave it to her.