A top-notch Mad Men 7.4, in which, among other things, a computer is installed in the office.
This gives Don a chance to wax philosophic to the computer installer about computers replacing people, which in turn serve as a potent metaphor for Don's return to Sterling, Cooper, et al. As Bert tells Don, the new company, in Don's absence, found it had no use for him. And as Bert savagely indicates, the company has no use for Don now.
Aside from the question of why Bert is being so vicious - I had the same question last week, and the same question about Joan's attitude towards Don - Bert's view of Don reflects just about everyone's in the company, with the exception of Roger; more about Roger in a minute.
Back to Don: Lou makes Don report to Peggy on the Burger Chef pitch. I honestly never heard of them, even though they were a real fast-food chain, with outposts in the New York area (Maybe their ultimate failure was due to Don not being in charge of their ad campaign). In any case, Peggy is more than happy to continue lording it over Don - yeah, I know she has more good reason to do this than does Lou, but even so - and the result is Don is driven to drink.
And who saves him? Freddy! There is a beautifully sad symmetry in this, given Freddy's past with the bottle. And this thread concludes with Don back in the office the next work day, ready to work at least for starters for Peggy. The opening of the elevator doors each time Don arrives at the office serves as a nice metronomic accompaniment of Don's voyage back, syncopated as we might expect in the dawning computer age.
And then there's Roger. His daughter has turned hippy, Roger is at first more reasonable than his ex-wife in trying to meet her half-way or more, but Roger fails in the end and walks off on a dirt road to catch a train home. This is the story not only of Roger, but of advertising in general. As Don explains earlier, it by no means always works.
But it's working just brilliantly as the storyline on Mad Men this year, which is having one of best half-seasons ever.