In this witty and charming love story perfect for fans of Sophie Cousens, Ashley Poston, and Josie Silver, a buttoned-up math professor is forced to rely on her carefree doorman when her identity mysteriously disappears.

Catherine Lipton carefully calculates everything, and not just because she's a math professor. She had a chaotic childhood growing up with a free-spirited single dad. So now, from her daily to-dos to her afternoon snacks, Catherine has a plan for it all. But sometimes she wishes she could be someone else, someone with a totally different life. Until suddenly her entire identity--from her Social Security number to her driver's license to her academic record--mysteriously disappears. There's no evidence Catherine Lipton ever existed.

With no ID and no other options, Catherine reluctantly accepts help from her exasperatingly laid-back--and infuriatingly attractive--doorman, Luca Morelli. Before long, by-the-books Catherine finds herself bending all the rules with the charismatic Luca--from taking meetings in smoky bars to breaking into hospital record rooms--and having a surprising amount of fun. As Catherine unravels the truth behind her identity's disappearance, she may discover that the real Catherine has been missing for a lot longer than she realized.