Jake and Felix must infiltrate Hayley's cheerleader slumber party in order to find out which girl is hosting a bug alien. Also, Stockey is nervous about attending his Troop class reunion.

On Halloween night, The Troop has to capture the monsters after the security system breaks down and the monsters escape.

When a veteran Troop member named Bianca Stonehouse replaces Mr. Stockley due to his dentist appointment, The Troop discover that she is a monster in disguise, there to help another monster escape and to find the real Bianca Stonehouse before its too late.

Felix's new friendship with Gus creates a rift within The Troop. Little does anyone know of Gus's secret plans to destroy The Troop.