Before The Battle Frontier

Since the gang wasn't going to be traveling through Kanto just yet, Ash was spending the day checking out all his Pokemon, talking to Delia more about his adventures in Hoenn and looking at his badges and other things he won during his journeys.
"I can't wait to start collecting the Frontier symbols and the contest ribbons." Ash told himself. 
Prof. Oak had given Ash, Tomo and May new Pokedex's and he updated Ash, Tomo and Max's Pokenav's to show them where the battle facilities were. The first one was near Cerulean City, so Misty agreed to join the group from there. May also got something else; the Squirtle she befriended wanted to join her so May had a new Pokemon.
Later on Mewtwo had a talk with Ash. Mewtwo wanted to travel across the Kanto region, since he hadn't been around Kanto yet.
"Be careful Mewtwo." Ash said. "Remember Team Rocket is still roaming around Kanto and I don't want Giovanni to try and capture you again."
'Don't worry.' Mewtwo said. 'I have been training myself to get stronger here at the lab. So I will be ready to attack Team Rocket if they find me.'
Ash was worried for his friend, but there was nothing he could do to stop Mewtwo.
'I must say Ash, I feel a power growing inside of you but it isn't your psychic power.'
"So have I, but I don't know what power it is." Ash said.
He told Mewtwo about the blue light he saw with his eyes closed and how it helped him around Granite Cave and other places without getting lost.
'I don't know what power that is, but it sounds useful.' Mewtwo said. 
"Yes, and I have this feeling that I will be finding out what this power is later." Ash said.
Truthfully Ash wanted to know what his new power was.
The next day...
It was time for the gang to start their journey through Kanto. Ash and Tomo were still wearing their Hoenn outfits. By now Ash and Tomo had decided what Pokemon they wanted to take with them. Ash had Manectric, Grovyle, Crawdaunt, Swellow as well as Phanpy and Larvitar. Phanpy and Larvitar wanted to travel again, so Ash agreed. Tomo had Growlithe, Elekid, Magby, Magcargo, Pelipper and Dusclops.
"Ash and Tomo you care of each other on your journey." Delia said.
"Don't worry Mom." Ash said. "Tomo and I will be home safely once our journey is over."
"Yes we will." Tomo agreed.
Then the gang said goodbye to Delia to start their journey.
But before they started to leave Pallet Town, Brock showed up. He heard that the gang was traveling through Kanto and Brock wanted to go with them. So with Brock back in the group, it was now time for the new adventure to begin.