Chapter 338: Stagestruck Starly is the first chapter of the DP Arc.
The butler Sebastian wakes a young lady, Platinum Berlitz, from her luxurious sleep on a very special day. Platinum slips a pearl ring—the ultimate in refinement—on her right hand, and on her left she wears a diamond, the ultimate toughness.
In Jubilife City, the Stand-Up Comedy Grand Prix: Bust-a-Gut is occurring. Diamond and Pearl are competing, but Diamond ruins their routine by eating, goofing off, and making a terrible pun onstage. Frustrated, Pearl grabs him and makes a run for it.
He then proceeds to ream Diamond out. He reminds Diamond of their inspiration, the comedy masters Blue Sky Pippin and Purin. Diamond, remembering, becomes serious, and Pearl promptly drags him off to practice comedy.
Back at the Berlitz Mansion, Sebastian frets over the danger Platinum will be in during the traditional Berlitz journey to Mt. Coronet's summit, where Platinum will collect the materials needed to forge a Berlitz crest. He tells her to meet her bodyguards, who will be wearing red and green scarves, in front of the Jubilife Building. Platinum leaves, letting out a sigh of relief. She releases Piplup to accompany her during the walk to Jubilife City.
Meanwhile, Diamond and Pearl's practice at comedy is not going well; Diamond can't seem to stick to script, instead cracking bad puns. They are interrupted by the producer of the comedy contest, who gives them a prize envelope for their "unique" flavor of humor.In his typical rush, Pearl crashes into passerby, all four members of the collision falling to the ground. Professor Rowan sits up and tells Pearl off harshly, quieted by his assistant, Mr. Berlitz's, reassurances. However, during the incident, Diamond and Pearl's prize envelope is accidentally switched with Mr. Berlitz's envelope of instructions for Platinum's bodyguards.
Diamond and Pearl go to where the letter instructs them, and as they happen to be wearing red and green scarves, Platinum mistakes them for her bodyguards (and they, thinking that the prize is a trip to Mt. Coronet, mistake her for a tour guide). Diamond is smitten with Platinum, dazzled by her beauty.
They are attacked by a flock of wild Starly, and, impatient, Platinum orders them to get rid of the Starly. They do so laboriously over the course of half an hour, using the Turtwig and Chimchar Platinum gives them.
Platinum, wondering if they are really professionals, decides to go on anyway. After refusing to tell Diamond and Pearl her name, they set off for Mt. Coronet.