Someone Else's Shoes by Jojo Moyes

Who are you when you are forced to walk in someone else's shoes?

Nisha Cantor lives the globetrotting life of the seriously wealthy, until her husband announces a divorce and cuts her off. Nisha is determined to hang onto her glamorous life. But in the meantime, she must scramble to cope--she doesn't even have the shoes she was, until a moment ago, standing in.

That's because Sam Kemp - in the bleakest point of her life - has accidentally taken Nisha's gym bag. But Sam hardly has time to worry about a lost gym bag--she's struggling to keep herself and her family afloat. When she tries on Nisha's six-inch high Christian Louboutin red crocodile shoes, the resulting jolt of confidence that makes her realize something must change-and that thing is herself.