There are certain parts of Pokémon Brilliant Diamond and Shining Pearl where you’re going to struggle to progress the game. For example, you might have trouble with getting past the Psyduck barricade alongside the Café Cabin on Route 210. Here’s what you need to know about getting past those Psyducks and proceeding through the rest of Pokémon Brilliant Diamond and Shining Pearl.
You’ll only be able to do this by progressing through the story. It’ll happen once you beat the Pastoria City Gym Leader, Wake, and earn the fourth Gym Badge. After that, you’ll have to deal with the Team Galactic force in the town and battle against them.
The next step is to wait for Cynthia to speak with your character. She’ll explain that the Psyduck blocking your path has an issue, and she offers you an item, Secret Medicine, that you can use to make them better and encourage them to move.
Now, with the Secret Medicine, all you have to do is return to the Psyducks alongside the Café Cabin and interact with them. You’ll see an exclamation mark above their head, and they’ll disperse from the location, allowing you to pass. All of this is story-related, so you won’t be able to miss any of these elements so long as you’re playing through Pokémon Brilliant Diamond and Shining Pearl.