This review contains spoilers. “You don’t have to worry about me” Don tells Megan in Mystery Date. After that little glimpse into your subconscious Don, I wouldn’t be so sure… A macabre fascination with the 1966 Chicago student nurse killings percolated throughout this gloriously dark episode of Mad Men, giving everybody something to worry about.  The inclusion of big headline news always runs the risk of turning Mad Men into a Wikipedia stub instead of the poised, revealing drama it is at its best, but like season three’s treatment of the JFK assassination, Mystery Date parcelled out its real-world shock neatly, using the Chicago murders as a backdrop for its characters to reflect on their own fears and weaknesses. It wasn’t all murder of course; the Chicago race riots were also name-checked, as was the continuing airline strike, and with the return of Greg Harris, the Vietnam War.  The episode may have focused on Mad Men’s women – Joan and her mother, Peggy, Dawn, little Sally and step-grandmother Pauline – but it was the male ego (or id, in Don’s case) that was really under the microscope in Mystery Date. Richard Speck’s monstrous act had Don hallucinating his guilt and self-loathing into a femicidal nightmare, Peggy admitted she imitated male behaviour to fit in at work, and failed surgeon Dr Greg was enjoying the ego massage his uniform and military status afforded him so much that he’d chosen a return to service over his wife and son. Christina Hendricks was once again fantastic as Joan, her performance in this week’s episode rivalled only by Elizabeth Moss’ comic, forthright extortion of hush money from Roger to cover up for his laziness. Peggy’s story this week saw her extend the hand of female solidarity to SCDP newcomer Dawn, but not before checking whether this incarnation of Don’s secretary shared her predecessor’s copywriting ambitions. Peggy embarrassed Dawn and herself with a momentary lapse in trust concerning a purse stuffed with cash (the same bigotry that made Lane not trust his African-American taxi driver to return that wallet in episode two), reminding us that however much a modern liberal she seems, Peggy is still the product of a racist society. Dawn provocatively leaving her thank you note atop the purse in question was a clear acknowledgement that while grateful, Peggy’s hesitancy at leaving her alone with the money had been duly noted. Speaking of great female performances, Kiernan Shipka as Sally rightly got the screen time she deserves this week, sulking and sassing Pauline like a real chip off the old Betty block. Sally was experiencing the summer holiday from hell, trapped in the Addams family-style home under the care of a grotesque guardian with a strange idea of what made suitable night-time stories for kids (and who offered up prescription sleeping pills before hot milk as a solution to Sally’s night frights). Incidentally, like Mork calling Orson, the phone call between Sally and Don should be made a mandatory part of every episode, so enjoyable was their shared mockery at how “important” Henry is.  All of which leaves us with Don, a man sick not just in the flu sense, but in the damaged psyche sense. Mystery Date was Don’s darkest episode since he spent that post-divorce Thanksgiving being slapped around by a hooker. Not only doesn’t he like himself, he also doesn’t trust himself, panicking in this episode that his taste for seedy adultery wasn’t just a phase, but a pathology he’s destined to repeat. It’s a little cruel, but Megan’s exasperated “How many times is this going to happen?” after running into yet another of Don’s past conquests raised a chuckle in my house. Somebody had better buy that girl a box-set.