Okay here's the plot for the aftermath of the movie.

Hopper manages to survive the bird after the bird was trying to feed her chicks, but Hopper wasn't eaten alive he missed getting eaten alive and a larger bird attacks the nest hitting the nest off the cliff, the next day Hopper lost his memory of the event that happened last night, after fighting to survive he stumbled upon a cricket outside of Ant Island

This will start they're adventure.