Very good show and I believe it's been renewed for another season.
The basic concept is a company that consults various government agencies (and occasionally other people) and helps them find out whether someone's lying or helps them find the truth. Their work is based on 'science', i.e. facial muscles automatically doing certain things (across all cultures) when you're lying and your not being able to change that fact. Very intriguing.
Additionally, e.g. a rough marriage for one of the team, dark and sad reasons why the head of the company first got into the area - sounds cheesy right now but works out really well.