In the final episode of the Pokémon: Diamond and Pearl series, Ash, Brock and Dawn's journey in Sinnoh comes to an end. Ash wants to be a Pokémon Master; Brock wants to be a Pokémon Doctor; and Dawn wants to be a Top Coordinator. As they prepare to say goodbye, Piplup, realizing that everyone is going their separate ways, runs away in tears. The gang finds Piplup and do one last battle against Team Rocket. Later at Twinleaf Town ferry port, Dawn thanks Ash and Brock for everything and wishes them luck on their journeys, while Ash and Brock wish her the same. Ash and Dawn exchange one final high five before boarding the ship with Brock. Dawn and Piplup look away, saddened, realizing they won't see them again. Ash calls out to them "No need to worry! We'll meet again someday!" Dawn and Piplup run down the dock and wave goodbye to Ash, Pikachu, and Brock before the boat leaves out of sight.
When Ash and Brock return to Kanto, they cross the familiar crossroads to their hometowns. Ash and Brock shake hands one last time; Ash wishes Brock good luck in Pokémon Doctor's School, and Brock wishes him luck in the Unova region. The two part ways for good. Ash sadly walks home, comptemplating his previous journeys with Misty, May, Max, Dawn, Tracey, and Brock. Before long, he arrives in Pallet Town and cheers up, ready to start his life anew.
- When James, Meowth, and Jessie are hugging each other and crying tears of joy, Jessie is missing her glove on her right hand.
- As of this episode, Brock and Dawn might never appear again. However, since Misty and May appeared the generation after they left, Brock may return later in the Best Wishes series as guests and Dawn was reunited with Ash in Rival Destinies.
- This is also the last mention of Misty, May, and Max.
- For the first time, Ash and Brock leave Dawn behind and go home by ship to their home region. In the previous series, Misty, May, and Max always left Ash and Brock behind and returned to their home region.
- This is the only final episode of a region not to feature a Pokémon from the next generation. However, Zorua and Zoroark appeared earlier in the season, in the season's movie.
- This is the last time Ash uses his Sinnoh team again for now.
- Just like the final episodes of the Original Series and Advanced Generation series, the "To Be Continued" graphic is replaced by "Next Time... A New Beginning!" due to the fact that the next episode starts the Best Wishes series.
- Giovanni's secretary is shown wearing the new Team Rocket uniform style.
- This is the season finale of Pokemon DP: Sinnoh League Victors and the series finale of Pokemon Diamond and Pearl.
- When Piplup cries, the song Tears After Cloudy Weather plays. This could be Wobbuffet's last appearance.