>>58615236Dawn was initially intent to go with Ash and Brock back to Kanto, who had offered her to stay with them, but a COTD fashion stylist asked for Dawn's Buneary to model for her Sinnoh fashion magazine, and Dawn for some reason decided that this meant she had to stay in Sinnoh and decline Ash and Brock's invitation. You know, because she couldn't have just given Buneary to her mom and had her take Buneary to the modeling gig, or something. Keep in mind, it was just Buneary; Dawn herself wasn't offered a modeling gig.
As for Serena, she finds herself unsure of what to do now that Ash's Kalos League challenge is over, Team Flare has been dealt with and Kalos saved, and Ash already has a flight arranged back to Kanto. Meanwhile, Serena has been offered an apprenticeship by a famous Pokémon Showcase judge (who had had an eye on Serena since her first Showcase performance), who was basically telling Serena that she would teach her exactly how to become Kalos Queen, since the current Kalos Queen had also been her apprentice. In the end, Serena, after a lot of mulling and introspection, and support from her mom and Ash, decides to decline the famous judge's offer, seeking to improve on her own more before accepting the offer of being an apprentice, and the judge, impressed, recommends Serena go to Hoenn and compete in contests, so that she can later apply the skills she learns in contests to her Kalos Queen goal when she returns. Serena agrees and decides to head to Hoenn.