Catherine Lipton plans everything. After a chaotic childhood, the stability of her life as a maths professor is essential, even if, just sometimes, she wishes she could be someone else, someone with a totally different life.
Catherine's tidy life is running smoothly until her entire identity - from her Social Security number to her driver's license to her academic record - mysteriously disappears and there's suddenly 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-book 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 realised.