James' dad arrives, and agrees to be the one to now officiate Barney and Robin's wedding.We also learn the Barney's mom and James' dad are now dating. William Zabka tries to sabotage Ted being best man (Lily tackles him).
Lily gets upset at him, so she gets out of the car, and takes a train to Farhampton. Lily is stressed about not seeing Marvin for a week, and The Mother comforts Lily by offering her cookies, which The Mother refers to as Sumbitches).Marshall's mom keeps posting annoying photos on Facebook, and puts one up revealing Marshall's new judgeship.Marshall freaks out, and refuses to get off the phone with his mother on the plane, while trying to talk her through how to remove the photo, before Lily sees it.Marshall's freak out causes him, and another passenger to get kicked from the flight.Loretta tells Robin to call her mom, when she learns that Robin's mom didn't board her plane for her daughters wedding.
Ted takes Cassie to The Farhampton Lighthouse, to try to attempt to date her, but she just further frustrates him (we haven't seen Cassie since this).
Barney introduces Ted to a few single ladies that will be at the wedding, for them to be his weekend date, and winds up getting stuck with Cassie, who winds up irritating Ted.
When the minster learns about the sinful ways Robin and Barney got together, has a heart attack and dies. Also, Marshall's new driving companion finds out about the impending fight between Marshall/Lily, and texts Lily about it.
The gift is then revealed to be the picture from the main credits (Ted has 2 more wedding gifts left to give). Lily learns about Marshall getting kicked from the flight, and might not make it to the wedding, which causes her to pay the bartender at The Farhampton Inn 0 to replace her glass of alcohol every time she isn't holding a glass (which becomes a running gag).
We learn that Ted had given the Locket to Stella back when they were dating, and that he went to L. After learning that James is getting a divorce, Lily drunk, tells Barney by mistake.
Marshall skypes with the two of them, and tells them to recreate the scenario while the two of them hold hands.