The Princess of Convenient Plot Devices Novel Volume 3 was written by Mamecyoro with illustrations by Mitsuya Fuji.

After coming face-to-face with her most haunting memories and staining her bodyguard Klifford's uniform with tears and snot, Princess Octavia barely has time to collect herself before she's dragged into an anti-royalist plot! Even worse, her brother's lover Sil, who she accompanied to the ball, has gone missing. She'll have to trust her masked potential (fake) boyfriend Rust—a notorious opponent of the crown—to guide them to where Sil is, but what will they find when they reach him?