Don deliberately delays returning an important call from California, because he knows it's bad news about Anna. Instead, he keeps himself occupied by forcing Peggy to miss her birthday dinner to pull an all-nighter with him for a client.
With another sale on the horizon, Sterling, Cooper, and Draper convince Lane Pryce to fire them and then join them as they start up a new advertising firm. At home, Betty follows through with her plans to divorce Don.
Don and Peggy prepare to pitch to Burger Chef, one day after the Apollo Moon Landing. Meanwhile, a power struggle in the firm between Sterling and Cutler leaves Don's future hanging in the balance.
Peter asks Joan to make an unspeakable sacrifice to help secure the Jaguar account, Peggy prepares to make a drastic move in response to Don's treatment, and Megan's acting career begins to create tension with her and Don.
Lane's entire world comes crashing down after getting busted for forging Don's signature on a check, and Sally experiences an awkward rite of passage while spending the weekend with the Drapers.
Don's journey ends in California with Anna's niece, Stephanie, where he contemplates his future. Roger decides to marry Megan's mother, Marie. Joan has a business proposition for Peggy, who is coming to terms with her feelings for Stan.
An old flame and potential client reenters Roger Sterling's life, Joan's husband searches for a new job, and Don finally comes clean to Betty about his true identity.
A peaceful hotel getaway ends in disaster for Don and Megan, an LSD trip could have a disastrous effect on Roger's marriage, and Peggy loses her cool after an unsuccessful pitch meeting.
The bosses come in from London to reorganize Sterling Cooper, but a key player's career is sidetracked by a freak accident. Meanwhile, as Joan prepares to leave her job, her husband gives her some bad news.
Don is stuck in Oklahoma after his car breaks down. Betty discovers that she is not in good health. Pete gets an unexpected job offer that could enable him to get his life with Trudy and his daughter back.