MAIN PLOT 1: A vast armada of powerful insect-hybrids has come to United Equestria with the intent of destroying the planet.

Main Plot 2: A mysterious perpetrator is out to ruin Spike and get him in trouble

Subplot 1: As Spike and Rarity prepare for their marriage, Spike still feels down about not knowing his roots

Subplot 2: Grand Ruler Celesto is struggling with an old painful memory of an old friend that died.

Warning: This is episode that I promised "YOU KNOW WHAT" for Cadance.