Milo faces down a cosmic storm made of negative probability ions, while Melissa, Zack, Cavendish, Dakota, Perry, and Doof work their way through the alien populace to save their friend.
Continuing from where the previous episode left off, Milo and the gang, now joined by a revived Cavendish, Agent P, and the "Cavenpus", arrive at the grounded UFO; only for Milo to once again be abducted by the same aliens.
Milo, Lydia, Coach Mitchell, and Scott get stuck in the Googolplex Mall elevator. Meanwhile, Doofenshmirtz and Dakota decide to finally attempt to search for Cavendish with the help of a "Cavenpus" clone made from Cavendish and Agent P's DNA.
After the school football field is ruined, an event that was meant to be there gets transferred to an old dilapidated park, where Melissa and Amanda compete over who can fix it up faster. Meanwhile, Dakota and Doof deal with an alien device that turns bones into a noodle-like substance.
Milo, Melissa, Zack, Mort, Bradley, and Amanda get in trouble with a substitute teacher and get detention. Meanwhile, the killer cyborg bear from "Now I Am a Murphy" returns to track down Milo and get revenge on him.
Zack and Milo join Melissa's athletically minded wrestling, speech, and debate team.
Six-year-olds Milo and Melissa meet for the first time, and Murphy's Law makes their first day of 1st grade a big adventure. Meanwhile, Dakota relates to Doof how he first met Cavendish while training to become time agents.
Milo, Zack, and Melissa attend a camp to learn new skills. Elsewhere, Cavendish mistakenly unleashes a giant alien.
Milo and Elliot accidentally get handcuffed together. Meanwhile, Zack and Melissa attempt to make a student film, but Doof messes everything up.
After Zack breaks his leg getting tangled in a harp while doing interpretive dance, all of his friends plan a "cast party". At said party, everyone shares stories of how they all broke something without Milo, Martin, or Murphy's Law around; as far as they know.
Milo attempts to escape his room so he can go out for the day with Zack and Melissa. Elsewhere, Dakota teams up with Doof to find Cavendish, who's attempting to show various news outlets a crashed U.F.O. with a malfunctioning cloaking device.
While attending a school award ceremony, Milo attempts to get to the stage in time to collect an award he was nominated for. Meanwhile, Diogee ends up riding along with two of Danville's police officers while they attempt to catch Zippy, the world's fastest koala, and rescue one of their K-9 officers.
Doof becomes inspired to find an "adventure buddy" to get over Agent P, and winds up joining Scott on a boat ride through the sewers.
After being told to go home again, Diogee crosses paths with Agent P and enemy agents after he swallows a flash drive disguised as a cookie. Meanwhile, Brigette makes Doof and Sara pick up dirty clothes, so the former builds a robot hamper-inator to do the job for them.
Eons in the future, an elderly man tells his grandson how a sentient crockpot of goulash came to be and defeated an army of robot screech owls. Back in the past, Milo, his friends, and Doof attempt to protect Brigette's goulash from Murphy's Law and Doof's hand-held-inators.
Milo gets abducted by the recurring alien characters introduced this season, while Melissa, Zack, and Doof attempt to look for him. While on trash duty, Cavendish sees the abduction from a distance, but Dakota does not. This causes a large argument between them, which ultimately ends in the dissolution of their partnership and the former going rogue.
While waiting for Milo to come join them for lunch, Melissa, Zack, Bradley, Mort, Chad, and Sara present "Neil From the Comic Shop" with differing theories on what Milo really is; ranging from him being a wizard, a supervillain, and a robot.
After an incident with a skydiving simulator, Milo, Melissa, and Zack are left in a cycle of falling and rising through the sky while Diogee tries to save them. Meanwhile, Cavendish and Dakota, while flying a plane and trailing a "Don't Litter Our Planet" banner, accidentally gain rivals in the form of Colonel Niblet and Lieutenant Tenant after taking the blame for Milo and his friends destroying one of their facilities.
After discovering a boombox in the attic, Milo, Martin, and Grandpa Murphy go camping so Milo can undergo a family rite of passage to become a "Murphy Man". While the men are away, the Murphy women and Doof go to an art museum to celebrate the day without Murphy's Law, but Doof causes chaos in its place.
Elliott gets hurt because of a Murphy's Law related incident, so Milo helps him with his second job as a dog walker. Meanwhile, Cavendish and Dakota discover an alien anti-gravity device and try to show it to Mr. Block for a promotion.
While heading to a mentor program she doesn't want to be a part of, Melissa ends up paired with Savannah on a mission to stop a rampaging robot that Milo and Zack accidentally built at the science fair before it destroys half of Danville.
When his Uncle Cornelius asks for help on his farm, Zack seeks out to prove to a doubtful Milo and Melissa that a "city boy" like him can handle the job. Meanwhile, on a nearby farm, Cavendish and Dakota are assigned to pick up a fallen UFO piece from a farmer who wants to become famous in the tabloids.
While Milo is sick, two shapeshifting aliens attempt to get a tissue sample. Meanwhile, under Monogram's orders, Agent P continues to keep Doof from doing harm while attempting to do good.
Doof shadows Milo to see how he navigates around Murphy's Law. Meanwhile, Cavendish joins an extraterrestrial conspiracy support group.
Amanda helps Milo, Zack, Melissa, and Mort prepare for an afternoon concert while aliens try to covertly study Milo. Elsewhere, Cavendish and Dakota find themselves losing time and not remembering why.
Milo and his friends try to save the old clock at City Hall that Melissa's great-grandmother designed. Meanwhile, Doof tries to help the city by removing sidewalk gum under Agent P's supervision.
Learning that the local skating rink is closing down, Milo convinces his parents to pursue their dream of winning a disco skating competition they were unable to finish years ago before that happens. Elsewhere, Cavendish and Dakota are assigned to pick up seemingly ordinary lawn gnomes from a little old lady.
Sara starts to go insane from Dr. Doofenshmirtz constantly invading her personal space, so he goes out with the rest of the Murphy family to try new things
Hollywood is rebooting the first Krillhunter movie with all women, so Milo and the gang help Tobias Trollhammer audition as a woman. Meanwhile, Cavendish and Dakota try to catch an alien while picking up trash by the highway.
Milo and Amanda get the chance to be on the latter's favorite TV show, Cake 'Splosion!, an extreme kids' cooking show.
Milo and Elliot are the pace car drivers for a charity race.
Milo and his friends and family decide to finally attempt to finish a board game.
Doofenshmirtz reminisces on an adventure he had with Diogee the previous summer after the canine got caught up in an Agent P style mission.
Melissa and Zack become determined to get a good picture of Milo for school Picture Day after learning he's never had a good one due to Murphy's Law; but Chad misinterprets this as Milo being a vampire and recruits Mort to help him prove it. Meanwhile, Cavendish and Dakota get new jobs at P.I.G. (Paranormal Investigation Group) and try to capture a Yeti on camera to impress their new boss.
After Scott the Undergrounder and Mrs. Murawski appear to hit it off and set up a date, Milo and the gang attempt to help the former look more presentable and normal.
In a similar vein as "Going the Extra Milo", Milo and Zack attempt to survive Murphy's Law while getting to school on a cold winter day while Bradley and Melissa bet on whether they'll make it on time again. Meanwhile, Cavendish and Dakota are forced to stand before the Time Council for their constant failures, resulting in their being fired and having their ability to time travel revoked.
Milo, Zack, and Melissa—with help from Phineas, Ferb, Candace, Buford, and Baljeet—help conquer Murphy's law to stop a swarm of Pistachions.
