This story is a sequel to Timeswirl

When Derpy decides to drop in to visit home, she discovers that she's been gone for longer than she intended, and another young mare expresses interest in joining the TARDIS crew. At the same time, something is very wrong with the mayor of Ponyville as he seeks re-election, as well as other ponies throughout the town. It's up to the Doctor and his two companions to find out!