I just finished reading Nanny Returns by Emma McLaughlin and Nicola Kraus. This is the sequel to The Nanny Diaries and picks up 12 years after the original book. You should probably read the original before the sequel though because a lot of the story deals with situations from The Nanny Diaries.
Nan Hutchinson was a nanny to Grayer X in the first book and now 12 years later, she and her husband, the "Harvard Hottie," have moved back to New York after living abroad. Grayer is now 16 and shows up one night on Nan's doorstep. She still feels guilty about what happened when she was his nanny and is dragged back into the drama of Mr. and Mrs. X and their new 7-year old son, Stilton. Nan is also busying starting her own consulting company and remodeling her house with her husband.
I found the book to be really slow during some parts but the last 100 pages or so I couldn't put it down because I was dying to know how it finished. The main characters are likable and it's hard to imagine people actually acting like they do in this book (think upper class of New York...aka The Real Housewives of New York) but they go into way more detail and description than is needed. Definitely not one of my favorites books (and I liked The Nanny Diaries better) but worth checking out and reading if you don't have anything else to read in the time being.