The Princess of Convenient Plot Devices, Vol. 6 (manga)

With the junior ball finally concluded, the enemy Adjutants defeated, and Sil safely retrieved, Princess Octavia is ready for a bit of peace and quiet. But just when she thought things would return to normal, she finds herself under house arrest-by Prince Sirius's orders! And to make things even worse, Sirius has her bodyguard Klifford detained for allegedly orchestrating Sil's carriage accident. Can Octavia clear Klifford's name in time? Or is there something bigger at play...?