The series "Pokemon: Sun and Moon" has been airing in Japan for nearly three months already, but Ash's Pokemon team is still considerably small. Ash caught Rowlet early in the seaon but has not really been in contact with other wild Pokemon since. In this week's episode, Ash befriends a Rockruff who is owned by Professor Kukui.

Ash discovers that Professor Kukui's Rockruff keeps disappearing at night and comes home in the morning with an injury. Ash and Kukui decide to follow Rockruff at night and witness the Pokemon participating in underground Pokemon fights. Ash decides to help Rockruff by training him which resulted to Rockruff learning the Rock Throw as a new move.

Subsequently, Ash's training pays off as Rockruff defeats Magmar who he was unable to beat the night before. Seeing the close friendship between his Rockruff and Ash, Kukui decides to let go of Rockruff so it can travel through the Alola Region with Ash and the rest of the gang.

According to Comicbook, while it is unusual how Ash obtained Rockruff in this week's episode of "Pokemon: Sun and Moon," it is not uncommon for regional professionals to give away Pokemons to trainers. Additionally, Ash lives with Professor Kukui so he will still be able to see his old friend all the time.

The next episode of "Pokemon: Sun and Moon" will see the return of the stray Litten that Ash bumped into several times throughout the series. It is also speculated that Ash will catch the stray Litten to add to his expanding Pokemon team.

Meanwhile, Team Rocket defeated Team Ash for the first time in 20 years in "Pokemon: Sun and Moon," so it will be interesting to see how Ash builds up his Pokemon team to make a comeback win against Team Rocket in the upcoming episodes.