Andy's trying to throw a fancy garden party at Schrute Farms, and of course no social event can happen without the entire staff present. He claims it's for no special occasion, but they sniff out that he's trying to impress Robert California. When in fact the truth is much sadder. He shows them all an online video from the garden party his parents threw for his little brother's promotion last week, complete with an impromptu musical duet between Andy's dad and his brother. So obviously he's hoping to recreate that moment with himself and his father. Not that anyone realizes this until much later.
In the meantime, the party is deeply weird, with Mose acting as the parking valet, everyone sucking up to Robert, and Dwight putting on bizarre displays he learned from a party hosting book written by James Trickington (actually Jim, once again not caring who else gets hurt if he can mess with Dwight). Andy tries unsuccessfully to force things, including a round of toasts that goes completely off the rails before it gets around to him like he'd hoped, but ends up stomping off in a snit when his brother and father end up hijacking what was supposed to be his musical moment. Shortly afterward, everyone learns via Pam's baby monitor what a complete prick Andy's dad is, and they understand him a lot better. Also, Angela and Pam both want to name their sons Philip, but Pam wins. Decisively.
Jim and Pam show up in the office in the morning, having seen one of the new Dunder Mifflin billboards on their way in. Apparently it features Andy's face, which he's all excited about, until Pam breaks the news that "somebody defaced it." Before he can get more details, Stanley comes in guffawing. Jim delicately talking-heads about how graffiti artists often fall back on a phallic theme, as we see three ad slicks showing Andy in various positions that could be interpreted as gobbling a giant, invisible knob (nobody said I have to be delicate). But we can assume that thanks to Scranton's street-artistic community, that knob is no longer invisible. Meredith comes in raving about the billboard. "Funny, edgy, right up to the line without crossing it." And that's the one with 20 dongs on it. Dwight enters and laughs, until he realizes he was in one of the photos too, and runs out screaming, "No! No! NO!" all the way until he gets to a partially-blurred billboard of Andy apparently cornholing him. Right up to the line, The Office.
Andy and Dwight are briefing the staff on the garden party Andy's throwing at Schrute Farms, telling them directions, and how it's more formal than a barbecue, basically everything but the occasion. Andy wants it to be super-fancy, like the one his parents threw after his brother's promotion. He pulls up a YouTube video from that event, showing his father (Stephen Collins) singing with his brother (Josh Groban). Stuntcasting: an excellent sign for this show. Andy points out his brother's boss in the background, which is when everyone realizes that Andy's throwing the party to impress Robert California. Gabe is furious in a TH: "Classic Gabe move!" Andy reminds them to be there at three PM, dress code "Connecticut Casual," whatever that means, and Dwight insists they go by the map he drew rather than looking it up on the web. So of course, back at his desk, Jim pulls up the street view to reveal that the GoogleCam van caught Dwight and Mose half-dressed on a seesaw. Dwight is in any case more interested in reading his book, The Ultimate Guide to Throwing a Garden Party, by James Trickington, and he's got the only copy in existence. Jim THs about how disappointed he is that his book only sold one copy. Oh, I get it, Trickington is Jim's nom de plume! Tricky...ng...ton.
Angela and Pam are having one of their usual pregnancy conversations in which Angela endeavors to makes Pam feel fat when Pam accidentally lets slip that the bun in her oven is named Philip, after her grandfather. She asks Angela to keep it quiet, but Angela was planning to use that name herself, after her favorite cat. I can fix this: the one born first wins.