Pocket Monsters stars a Pokémon Trainer named Red and his rude Clefairy. It is chiefly a gag manga, using crude humor and slapstick.
The series diverges somewhat from the Pokémon video game and anime canon: most Pokémon can speak human language and regular animals (like birds and fish) appear alongside Pokémon. Evolution is also significantly different in Pokémon Pocket Monsters: Pokémon can evolve at any time, and they are also able to reverse the evolution.
-Bulbapedia

In a world filled with talking Pokemon, Red and Green compete with each other in a race to gather all the data needed for the new Pokedex! Bumbling Clefairy frustrates Red with its extreme incompetence and silly behaviour… however, sometimes Clefairy's bizarre ideas to work out in the most surprising ways!!
-Chuang Yi