Home on the Rang-Ranch
This ranch is a lot bigger than it looks on the outside. Trying to get into the western part leads you to a battle with your rival, who has the same starter and moves, albeit at level 8, despite all three of the starters should have learned a STAB (Same-Type-Attack-Bonus, a move of the same type as the user) move that beats your starter, but this makes it more fair. After defeating him, you hand over the Town Map, and the owners of the ranch, a husband and wife, enter. The wife gives you a potion and asks if you have seen their missing Herdier. Your rival, enraged at them for not keeping watch of their Pokémon, goes to look for it. The couple stays there and the wife will heal your Pokémon for free as a means of thanking you for helping. Looking around, it seems you will have to search north to find it, but there is a Poké Ball lying in the pastures by the Lass trainer. Your rival gives you a Paralyze heal close by the Janitor in this area, probably due to said janitor having a Mareep with Static, which has a chance to Paralyze your Pokémon if they make contact. Also close to a Youngster to the right of here is an X Attack, so you can pick that up in preparation for the gym battles ahead. Making your way eastward, you can hear the Herdier barking, and soon enough, encounter the Herdier being cornered by a man in darker clothes.
While you approach the man, he panics and throws a TM at you, specifically, TM 21: Frustration. A physical Normal type move with 100% accuracy that varies power based on happiness, gaining power the less happy the Pokémon is with you. The man makes a mad dash out of there, while the Herdier shows gratitude for saving it.
The owners thank you for finding their missing Pokémon and your rival leaves, probably out of frustration that someone would be "careless" with their Pokémon.
New Pokémon can be encountered in this area, starting with the Pokémon you will find most often here, Lillipup. Lillipup is a really good Normal type, way better than the Patrat from Route 19. In fact, this is probably the best Normal type you will get in the entire game, as everything either is frailer or does not hit as hard. When Lillipup evolves, it gets one of two abilities: Intimidate and Sand Rush. The former being an Ability that drops the foes Attack just by having it enter the field, and the other doubling Speed when in a Sandstorm. If you happen to get something that can learn Sandstorm (as the Lillipup family cannot learn it), then you have quite the force on your hands.
Second is Azurill. Azurill starts as a Normal type, but it evolves into a Water type for some reason. Azurill starts out somewhat weak, being the weakest Baby Pokémon as of Generation VI. However, similarly to Lillipup's evolution, the stats aren't all to be admired, as Azurill and its family are bestowed with the amazing Ability: Huge Power. Huge Power doubles the Attack Stat of the Pokémon that has it, which effectively turns the Base 50 Attack stat its final evolution gets into a 100. While it is not as strong as, say, Mega Mawile from X and Y, it is still a force to be reckoned with. Numerous people use Belly Drum to get this things Attack stat sky high, and sweep entire teams with it. However, despite all of that, there is the chance to get one with Thick Fat, which is somewhat useless on Azurill and its family, as they will resist Fire and Ice normally just by typing. Another thing is that it does not get the almighty Aqua Jet unless you breed it, so priority is not an option. However, don't let that drag down Azurill's usefulness. Fun fact, due to an oversight of the programmers since Ruby and Sapphire, 1/3 of all female Azurills will evolve into male Marills, and it still applies in these games.
Third is Psyduck. Psyduck is a Water type that is very mediocre. It gets good moves, but it does not have that great of stats to back them up. Chuggaaconroy said it best when he said it was a "short term solution." It can work, but there are better water types in the game.
Next is Mareep, a classic. While Electric types are known for their speed, the Mareep family are more bulky, which is not very bad for an Electric type. It has power behind it, and can be used as support for a team. However, as stated earlier, it is slow, so do not expect this thing to be going first too often.
Finally is Riolu. Riolu and its evolution, Lucario are debatably some of the best things to come out of Diamond and Pearl, as they have good offense, good speed, and deep movepools on both special and physical sides. As a Fighting and Steel type, it has some handy resistances and good moves to help cover it. There is not much to be said about this Pokémon that has not been said already. The only downside is that Riolu is a little bit on the weak side for a while, but evolving it will not take much longer than the second gym (however, that may be a little too late for some.)
With Herdier safe, and your rival having the map he needs, it is time to return to Floccesy Town to talk to Alder again.