Melissa and Zack throw Milo his first surprise birthday party, the only real birthday party he's ever had. Milo, Melissa and Zack go with their classmate Amanda to an opera concert for extra school credit.
In Family Vacation, Milo interrupts another family's vacation and shows them the joys of going with the flow instead of planning everything. In Murphy's Lard, Milo, Zach and Melissa enjoy a day at Lard World and Melissa overcomes her fear.
While trying to ensure that the pizza they ordered arrives safely, Milo, Melissa and Zack start sharing secrets. Milo, Melissa, and Zack compete for the school against another school in the acadecamathalon, combining academics and sports.
A jaded substitute teacher re-discovers her love of teaching after an encounter with Murphy's Law. Cavendish and Dakota discover that they are considered low-level employees, and Zack's father gets his first experience with Murphy's Law.
Elliot wakes up one morning to find Milo has been erased. At first, he's overjoyed but soon becomes bored. Milo runs a race but needs an assist from Melissa and Zack. Cavandish and Dakota find themselves in the Old West and meet Milo's ancestor Sheriff Murphy.