On July 1st, Sterling Cooper finds out that three people from PPL are coming in from London for a two-day observation the next day. Everyone has to organize their desks and prepare presentations which becomes an annoyance because July 3rd was supposed to be a holiday. It is also Joan's last day at Sterling Cooper. The other girls are preparing a surprise party for her. It doesn't stay a surprise for long, though.
Greg shows up at the house late that night, drunk. He tells Joan about the Chief Resident position and that they told him he would never be a surgeon in New York and that Joan must work after all. What horrible timing...being that Joan is no longer at Sterling Cooper.
The next day, the visitors arrive with a new man in tow. They have a meeting with Pryce and tell him he is performing well and move him to the Bombay office.
Everyone then finds out that the new guy, McKendrick, will be taking over the office with Don and Cooper. Roger is left out of the hierarchy at first but they say it was just a mistake - maybe things aren't going so well for him after all. The visitors then go to the rest of the office for a champagne toast for the good news and Joan's last day.
The office is given the rest of the day off. Smith discovers the John Deere riding mower that Ken brought in the day before as a sign that they landed the John Deere account and decides to let Lois drive it...too bad she is drunk and doesn't know how to drive it. She rides right over McKendrick's foot. Joan jumps in and saves McKendrick's life but his foot isn't looking like it's in great shape and Pryce has to stick around for a while longer after all.
Don misses the office drama as he is meeting with Mr. Conrad Hilton, who ended up calling him in for some free advice for his next ad campaign. Mr. Hilton is looking like he could be Don's next client. Don gets a call from Joan about McKendrick and heads to the hospital, sadly saying goodbye to Joan.
Don is having a hard time at home because Sally won't sleep with the lights off because she is terrified that Grandpa Gene is haunting her through her new baby. Don and Betty get into a fight about naming the baby Gene and Don finally convinces Sally that the baby means no harm.