A Treasury of the Familiar Volume 2 by Ralph L. Woods

After their close call with the archdemon Thel’al, Astria and Lesti are finally given permission to leave the academy grounds. Eager to get out into the city, they head to the market. Almost immediately, they hear whispers of strange happenings in the city. Unable to ignore the problem, they begin to investigate on their own.
Meanwhile, back at the academy, Lesti finds herself in a new class. In fact, it’s the top class in her year! With a unique chance to make friends, she doesn’t waste any time. However, Astria has her concerns. The girl she befriends, Aurelia, is acting suspiciously. Will Astria safely navigate Thel’al’s schemes and find the secret behind Aurelia’s actions, or will her curiosity spell doom for the Astral Cat? Goodreads

Summary

The second volume picks up after the initial conflict with the archdemon Thel’al. Astria and Lesti—now free to leave their academy—venture into the city, where unsettling rumors soon draw their attention. Lesti, placed in the top tier class, forms a new friendship with Aurelia—but Astria feels uneasy. As mystery and intrigue unfold, Astria must rely on her instincts to protect Lesti from unseen dangers.