If this season of Mad Men were a novel, episode ten would serve as its darkest hour – the moment in the story where everything teeters on the brink of collapse, and the future looks uncertain for almost every character involved. Over the course of Mad Men’s previous three seasons, we’ve seen how ad man Don Draper has carefully built up his persona around him like a nest. Having borrowed the identity of a deceased soldier he served with in the Korean War, Don (née Dick Whitman) reinvented, chasing his own version of the American dream, and acquiring huge success along the way. In a season that has seen Don Draper’s life gradually unravel – he’s already dealt with a messy divorce, alcohol addiction, Chicken Kiev and the sudden death of his secretary – the season reaches its tenth episode with the possibility that his true identity may about to be discovered. Ironically, it was a form that Don had signed that triggered the appearance of the G-Men at Betty’s house. New clients North American Airlines, who in turn have a contract with the US government, had requested background checks on SCDP’s employees – including Don Draper himself. In a panic, Don demands that Pete – who stumbled upon Don’s secret back in season one – end SCDP’s dealings with NAA before it’s too late. In the midst of all this drama, Mad Men’s writers still find time to cram in a plot strand about Lane and his sadistically abusive father (who, in a scene of startling brutality, strikes him around the head with a cane) and a quietly tragic moment where Joan awaits an abortion. In lesser hands, moments such as these could descend into mere soap opera, but the sensitivity of Mad Men’s writing and acting places it in a higher league. With all the shouting and angst elsewhere in the episode, it’s Christina Hendricks’ quiet performance as Joan provides a moving counterpoint. It’s an episode filled with secrets and lies, with Roger just about keeping a lid on the potentially ruinous departure of Lucky Strike. And while Pete may have helped keep Don’s identity a secret for a little while longer by ending the NAA contract (provoking a stinging attack from Roger in the process), how long can SCDP continue with the loss of two such lucrative clients? There are just three episodes left in season four, and the future of Mad Men’s central characters has never looked more precarious. I can’t wait for the next instalment. Read our review of episode 9, The Beautiful Girls, here.