Max and Shred are left in charge of the Junior Porcupines and are each determined to take the scouts on the best camping trip ever. Abby gets an unusual job at the Yogurt Yeti.
Shred takes things too far after he discovers the joy of playing pranks; Diane tries to get a possum out of the house; Lloyd tries being the 'bad cop' parent.
Max and the gang's trip to Switzerland for a major race gets foiled when Yud Nuuderuud blackmails them; Howie builds a home security system for Lloyd.
When Max becomes homesick, Alvin, Howie and Abby try to cheer him up by throwing him the best birthday party ever.
Howie enlists Alvin as her assistant for a youth science fair competition; Max and Abby must put a stop to Diane and Lloyd's table tennis addiction.
Alvin goes to extreme measures to hide his allergies when Max's dog shows up in Blizzard Springs; Abby turns to Kaylee for help after failing at her first attempt at improvisation.
The family is surprised when Alvin suddenly has a girlfriend, but quickly grow fond of her. Max however smells a rat and stands up for his best bud when he thinks this new love is just using Alvin for student government gain. Howie is testing the intelligence of a pig, but runs into trouble when the Ackermans keep treating it like a pet.
After Alvin claims not to have any fears, Max, Howie and Juliet set out to scare him. But with Diane and Abby away at a college interview, Lloyd is left in charge and does not know how to handle a potential ghost in the house.
Alvin and Juliet have been dating for a while and Juliet wants their parents to meet. But what seems like a harmless idea quickly escalates into the parents forbidding Alvin and Juliet from seeing each other anymore! At the same time, Max and Abby discover Howie has been keeping an amazing snow fort secret from them.
Alvin forgets an important anniversary with Juliet, then makes things worse when he tries to follow the not-so-sage love advice of everyone in the family. But eventually, with Abby's help, Alvin finds the confidence he needs to win back Juliet back. Meanwhile, Max meets his second biggest fan, Harley, and Howie's not happy about it.