When Nate and his two friends go to the park to play football, things aren't normal. The weather, the odd smells in the breeze, and most notably the squeaky voice that seems to come from nowhere. Nate and co. might not know it, but Twilight Sparkle and co. will:

Pinkie Pie has gone transdimensional.

Which also means Nate, Teddy, and Francis are in for one heck of an adventure.