Special animation made to commemorate Pokemon Day 2025. 

This short follows the story of Hana, a young girl who lives in Paldea and admires the Dragonite postman. She aspires to become a postman but one day finds a letter with no addressee so decides to try and help find the send with her partner Fuecoco. When they find the sender, a boy named Rio, they learn that Rio sent the letter to celebrate the birthday his father who lives in Kanto, and to make it worse, the birthday is today. It's up to Hana, Rio and Dragonite to get the letter to him as soon as they can. 

(Source: Serebii, edited)

Kairyuu to Yuubinya-san