Young crown prince Cecil of Alphasta is so brilliant that everything in his life is easy to the point of boring him. Then one day, his 8-year-old fiancée Bertia suddenly said, "Prince Cecil, I am a villainess!" Claiming that this world is the same as that of an "otome game" from her past life and that she is playing the role of the "villainess" in it, she aims to play her part well and have their engagement annulled. With that goal in mind, she sets about causing turmoil in Cecil's daily life!