Allison, a dermatologist who works in her father's practice, meets Amy, a quirky and blunt woman who claims to be her guardian angel. Having watched out for her since childhood, she now decides to openly help Allison by giving her life lessons. At first, Allison does not believe her, but Amy gains her trust by knowledge of her secrets and predictions that turn out to be true, most importantly that her boyfriend Evan is cheating on her with her best friend, Jill.