Following A Maiden's Voyage (Japanese: 旅立ち！フタバタウンからマサゴタウンへ！！ Setting Off! From Twinleaf Town to Sandgem Town!!) is the 1st episode of Pokémon: Diamond and Pearl.
In the far-off region of Sinnoh, a girl named Dawn is finally 10 and has set out from her hometown of Twinleaf to meet Professor Rowan in Sandgem Town to receive her Starter Pokémon. Her dream is to take part in Super Contests positioned throughout the land. On her way, however, she gets lost. Meanwhile, at the lab, Professor Rowan's assistants are chatting while examining and feeding the three starter Pokémon. Two other assistants arrive in the room with a Starly and Staraptor. However, Chimchar steals the last of Piplup's food. Piplup angrily protests, but the mischievous little fire-monkey pulls down his eyelid and sticks out his tongue, then shakes his butt at Piplup while waving, taunting. Piplup begins attacking Chimchar with bubbles while Chimchar runs around the lab. While trying to keep Piplup under control, the chaos cause Starly and Staraptor to lose control, who begin flying around and wrecking books and papers. The gust breaks a window in the lab, allowing the two birds to fly through an open window, followed by Chimchar (who pulls down his eyelid at Piplup one last at Piplup, the latter in hot pursuit). The assistants plan to clean up, but as they begin, Professor Rowan arrives with Dawn.
With only the Turtwig remaining, after getting glared at by Rowan, continues to eat its food, Dawn asks and is allowed to go and search for the four missing Pokémon. After receiving some tips from Prof. Rowan, Dawn runs off towards the forest where the Pokémon were headed. Before she reaches the forest, however, she runs into Chimchar and Piplup, Chimchar still swinging away from Piplup's bubbles. Dawn attempts to calm them down, but they ignore her, Piplup changing its target to her briefly before both disappear into the forest. Dawn runs into the forest after them, only to hear Piplup's cry. She runs toward it, seeing Piplup as well as several other Pokémon trapped in a web created by an Araidos. The Ariados notices Dawn, chasing her through the forest. Dawn quickly hatches a plan, causing the Ariados to destroy its own web, making Piplup land safely in her arms. However, after sliding down a hill, Piplup seems very indignant, using Peck on Dawn several times. Dawn begins to berate it, afterwards Piplup's stomach begins to growl but then realizes that it is simply hungry. Although Dawn offers it Pokémon food, it seems disdainful and won't eat it. This scene is interrupted when several Ariados return, attacking Dawn and Piplup with several of its friends.
Trapped in a cage created by String Shot, Dawn distracts the Ariados by tossing the Pokémon food at them while Piplup destroys the cage with BubbleBeam. Unfortunately, before Dawn can escape with Piplup, an Ariados trips her with String Shot. Piplup steps in and uses Bide to absorb the attacks of the Ariados, then destroys them and the cage with a massive energy wave. Shortly after, the Piplup faints, exhausted from having taken all the attacks and the energy used.
While walking through the forest, Dawn stumbles upon Lake Verity. Piplup wakes up, recharged, but its stomach begins to growl again and still hungry. Dawn looks into her Pokémon food can, noticing that she only has three pieces left. Despite being disdainful earlier, Piplup accepts the food. She then spots Staraptor carrying Chimchar back to the lab, with Starly close behind. Before they can return to the lab, however, the lake ripples, and a mysterious figure appears for a moment before vanishing. Upon returning to the lab, Dawn asks Professor Rowan about the figure. He notes that it could be the legendary Pokémon of the lake. Shortly after, Dawn is presents with several Poké Balls and a Pokédex. Lastly, Rowan asks Dawn which Pokémon she wants for a starter. Much to Chimchar's obvious disdain, Dawn immediately chooses Dawn's Piplup, noting that they are already a team. Dawn then sets out for her Pokémon journey in earnest, riding away from the lab, with Rowan and his assistants waving her off.
At the same time, Ash, Pikachu, and Aipom are on a ship bound for Sinnoh. Ash boasts about becoming the Sinnoh Champion while Jessie, James, and Meowth watch from below decks. Later, Ash discusses Aipom accompanying him to Sinnoh with Professor Oak, who notes that he will send Aipom's Poké Ball to Professor Rowan. Before they continue, though, Team Rocket quickly snatches Pikachu from their balloon. Before they can leave, Meowth begins to argue with Jessie, attacking Wobbuffet with Fury Swipes. Wobbuffet then uses Counter, destroying the balloon and sending Pikachu falling into the forest. The episode ends with Ash and Aipom running after Team Rocket, while Dawn cycles away from the lab.