Imperfect Angel by Christi Barth

Three days ago, all Maisy Norgate had was a stack of bills, about a gazillion jobs, and her sunny-as-hell outlook. Now, thanks to an uncle she never knew about, she’s inherited an ornate skeleton key with absolutely no idea what it’s for—or why she has it. Which is exactly when a ridiculously handsome guy claiming to be an angel shows up at her door and all hell breaks loose…
Nephilim Rhys Boyce cannot believe that Maisy is the new Keeper of the Key. Why would anyone bequeath this warm, bubbly redhead the key to Hell? And to make matters worse, she’s given the key to the first person who asked for it. A demon. Yep, Maisy is determined to make his job—not to mention some seriously inconvenient temptation—as hard as possible.
First a half angel with a very human chip on his shoulder must find a way to convince Maisy that angels and demons do exist. Then Rhys will have to break the really bad news…that she might have accidentally ended the world.