Sara wants to go see The Doctor Zone Files movie with Milo, but worries about potential problems.

It's career day and Milo is having a hard time deciding what his career should be. He tries to decide while visiting the water works, fire department, and hospital. But of course, everything goes wrong. Meanwhile, Dakota and Cavendish try and make sure a truck full of pistachios makes it to the pistachio warehouse.

When Milo accidentally joins another family on their vacation, the new family must learn to cope with Murphy’s Law.

Milo and Melissa share their most embarrassing stories, but Zack refuses to reveal his past.

When Melissa’s dad drives her and Milo into town on a decommissioned old fire engine, chaos ensues.

When Cavendish and Dakota stop Milo from destroying a pistachio plant, they change the future. Pistachio plants become sentient and take over the planet, so Cavendish, Dakota and Milo must race through time to save the future.

Parents become children at Back to School Night.

Dakota travels back in time to save Cavendish.

Milo, Cavendish, and Dakota travel back to 1965 and inspire the creation of Dr. Zone only to encounter a sinister plot to take over the world.

Zack doesn’t think anything about Halloween can scare him anymore, but he didn’t account for Murphy’s Law.

Milo surprises his parents by inviting the extended Murphy family to town for Christmas, multiplying the effects of Murphy’s Law.

Milo, Zack, and Melissa—with help from Phineas, Ferb, Candace, Buford, and Baljeet—help conquer Murphy's law to stop a swarm of Pistachions.

Milo and his friends and family decide to finally attempt to finish a board game.

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.

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.

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.

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.

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.

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.

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.

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.

Zack and Milo join Melissa's athletically minded wrestling, speech, and debate team.

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 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.