The Princess of Convenient Plot Devices Novel Volume 5 was written by Mamecyoro with illustrations by Mitsuya Fuji.

Princess Octavia and Prince Sirius set off on their official survey of the castle town even as they brace for an anti-royalist attack. In truth, Octavia is doing everything she can to create an opportunity for them to strike! She hopes to prove Klifford's loyalty by seeing how he responds to such threats. Rather than a nuisance, Octavia's scheming might be exactly what they need! Her efforts reveal hidden agendas, family secrets, and lost memories—with all clues pointing to enemies hiding among those closest to the royal family.