Phineas and Ferb: The CountDown Aftermaths - Part I

The CountDown Aftermaths - Part 1 is the first part of the Phineas and Ferb episode special. It aired on October 6, 2021, before the second part on October 13, 2021. It takes place shortly before Act Your Age, and involves Heinz Doofenshmirtz building an explosive bomb that ruins Danville.