Bella, a powerful demon and the Overlord of Contracts, is shocked to wake up as Isabella Dunkeld. Although she is called a villainess for her sudden whims and unruly behavior, to Bella, Isabella is just a frail young lady with no one to rely on. With her mana sealed away, Bella must now find out what contract Isabella made and why she ended up in her body... but blending in with humans won't be so easy. Will Bella regain her power and save them both, or will her ways just cause greater havoc?