While putting Maggie to bed, Marge discovers Maggie is too clingy. After Maggie's attachment to Marge causes a jar of milk to be spilled, Marge attempts to email Creative Responses for Infant Edu-loving ("C.R.I.E.") pronounced as the word cry, a group which enables attached children to be more independent, with the intention of finding a counselor for Maggie. Meanwhile, Homer finds out the Kwik-E-Mart and Moe's Tavern do not have any more milk; Moe even charges him for accidentally serving him white paint, so he takes a trip past Shelbyville and Ogdenville to Guidopolis, a sleazy-looking town populated by Italian-American stereotypes.
He goes to the "Mook-E-Mart", purchases milk, and winds up having his car towed by a man named Louie. After noticing Homer's fascination with towing, Louie releases Homer's car and introduces him to the joy of towing cars for a living. Louie decides to help Homer become a tow truck driver, if, and only if, Homer will "stay off his turf". Homer agrees, and becomes Springfield's official tow truck driver.
At home, a CRIE woman arrives to help with Maggie's independence. After the woman orders Marge to leave Maggie alone in the room, Maggie's crying makes Marge desperate to hug Maggie; when the woman explains that "hugs are drugs, and Maggie is addicted", Marge ignores her, kicks her in the groin, and rushes to the living room to find a newly independent Maggie spelling IMOK ("I'm Okay") on her building blocks. Later, a more independent Maggie climbs on a table leg in the kitchen, picks up a book and banana and seats herself in her high-chair, much to Marge's sad disappointment that she is no longer needed.
After towing the Rich Texan's limo, a newly successful Homer goes so far as to tow down Arnie Pie's helicopter. After a brief celebration at Moe's, he then tows Lenny's car, Principal Skinner's car, and even the Sunday School bus (which he tows with the kids still in it), causing Ned to sardonically call Homer, "Towmer".
The residents of Springfield become frustrated with Homer's continuing towing antics, prompting them to plan revenge upon him, with invaluable help from Agnes Skinner, a four-time widow — on the last three occasions, by tow truck drivers. After leaving a car in Guidopolis, they spray on a handicap parking logo, stuff multiple tickets under the windshield wipers, leave it beside a fire hydrant, and attach an incomprehensible license plate.
They cover the Guidopolis city limits sign with one saying "You're still in Springfield", with the intention of luring Homer to Guidopolis, where Louie had forbidden him to go. At home, Maggie makes a baby book including her toenails and hair. After seeing her more independent, Marge begins to miss her, so she bonds with a sack of potatoes. At Guidopolis, however, Homer is abducted by Louie who keeps him in his basement with other tow truck drivers who trespassed his area, where he bonds with them.
Homer's absence causes parking pandemonium. Lenny and Carl smugly park their GMC in the handicapped area, prompting an angry, handicapped Mrs. Skinner to park sideways. Rainier Wolfcastle parks his Hummer on top of her in spite. Duffman lowers his blimp into a no-parking zone, where it is shot by the Sea Captain, causing it to deflate onto the pavement. A train engineer however, crashes through it all. Marge, meanwhile worries about Homer, who has not returned home for four days.
Maggie, worried for her father and mother's happiness, uses her newfound independence to save Homer by riding on Santa's Little Helper through the night to Guidopolis. A humble Maggie rescues all the tow truck drivers from the cellar by attaching Louie's towhook to the cellar window bars (unbeknownst to Louie) and returns home with Homer (as a reward, Homer gives Maggie back her "nose", but gives her Lisa's instead). After giving the sack of potatoes a punch, Maggie gives Marge her pacifier and hugs Marge, reuniting with her.