The owner of the firm's accounting firm wants them to help her fire one of her employees for lying on his application. Harvey tells Mike to do all the paperwork which includes the back ground check which proves his duplicity. And when they meet the man, Mike lets it slip that they didn't know the truth about him recently but for several years. That's when the man claims that this is about something he discovered about their practices. So Mike sets to find out if what he is saying is true. Harvey at first doesn't want him to do it but thinks something is going on.