When guardian angel Harry Mills arrives on Earth for the first time, he's got a lot to learn about life as a human. But this miracle worker-in-training ignores the advice of his seasoned heavenly mentor, Celeste, to eagerly take on his first assignment-helping a young woman named Addie find the confidence to change her life. Now, after her father's sudden passing, Addie is living with her mom Sharon, filled with regret and uncertainty while attempting to finish her degree all while avoiding her childhood nemesis and neighbor, Erich. Enter Harry, posing as her fumbling, well-meaning new English teacher who takes on the task of guiding her to see the wonderful things she can't see in herself. With a deadline of Christmas day to change Addie's perspective, or else say goodbye to his own Earthly existence, Harry is clueless but endearing in his effort to make Addie open up to a life full of promise-and even love-while learning a few life lessons of his own along the way.