Dog Man: Mothering Heights (2021) is the 10th installment of Dav Pilkey’s Dog Man series. The Dog Man series is a spin-off of Pilkey’s extremely popular Captain Underpants series, which comprises 12 novels. In Dog Man: Mothering Heights, Chief and Dog Man are challenged by two giant sippy cups, which rampage through the city. Meanwhile, Petey is reminded by Li’l Petey, as well as by memories of his mother, that love is more important than material possessions or the good opinions of strangers. The graphic novel, which is aimed at middle-grade readers, reminds readers of The Power of Love and The Value of Creativity. It also represents Silliness as Joyful and Important.

This guide is written with the 2021 Graphix edition of Dog Man: Mothering Heights.

Plot Summary

The story opens with Chief, the police chief of the town, being awakened by a phone call telling him that Dog Man, a member of the police force who is half dog, half man, has been injured. Dog Man is Chief’s best friend, and Chief runs, panicked, to the hospital, not even taking the time to change out of his pajamas. Chief, who believes that Dog Man was injured in the “Line of Duty,” is annoyed but relieved to learn that he misheard on the phone. Dog Man was injured in the “Line of Doodie,” the line for the bathroom: His fingers were slammed when the seat fell as he was drinking from the bowl (24-25).

Chief walks Dog Man home. On their way out of the hospital, Nurse Lady compliments Chief on his duck slippers; Chief is flattered and excited by this. Dog Man is upset that he has to wear a cone for a few days while his injured hands heal. He is comforted by Li’l Petey, who is playing at Dog Man’s house with 80-HD, a robot who is Li’l Petey’s friend. Li’l Petey and 80-HD design a mechanized cone that transforms into a suit of multipurpose machinery for Dog Man. Dog Man happily puts on the new cone, called the Cone of Destiny, and cheerfully leaves for work, knocking Petey, who has come to retrieve Li’l Petey, on his way out.

Petey instructs 80-HD to repair the parts of the house that Li’l Petey and 80-HD damaged while they were playing the day before while he bathes Li’l Petey. Petey explains that he has an important interview that day with Sarah Hatoff, an investigative journalist who is doing a story on Petey’s transformation from a villain to a law-abiding citizen. Petey wants no distractions and is put out to learn that Li’l Petey has already invited Molly, his best friend—who Petey thinks is a little strange—over for a playdate. Petey instructs the two friends to go downstairs and be quiet when Sarah and the camera crew arrive, but instead, Molly and Li’l Petey loudly sing toilet humor songs and pester Petey for snacks and drinks. Meanwhile, Sarah continually interrupts Petey whenever he goes to answer a question with another question. Petey grows increasingly frustrated. He tells the children to clean up their cups after themselves, but instead, they discard their sippy cups at the top of the stairs.

Meanwhile, at Cat Jail, Grampa tries to escape through the Cupcake Exit, but Big Jim has reprogramed it to punch anyone apart from himself or his cardboard robot, which isn’t sentient yet; Grampa is punched in the face by the gloved fist on a spring. Grampa tricks Big Jim by getting into the cardboard robot and pretending that it has come to life, which allows Grampa to escape from jail with Big Jim. Set on causing disruption and mayhem as usual, Grampa sets off, with Big Jim in tow, to find Cannery Grow, which makes things grow in size, and Living Spray, which brings inanimate objects to life. He convinces Big Jim that these things are necessary because “cupcakes are delicious forever” (76), which convinces Big Jim, whose alter ego is Commander Cupcake, a cupcake-loving hero.

Dog Man’s colleagues laugh at him in his cone, but he reduces them to trembling when he transforms himself using the Cone of Destiny’s transformation button. Dog Man sits with Chief as he tries to decide what to write in a love letter to Nurse Lady. Dog Man tries to help Chief by leaving a slobbery pile of roses that Dog Man dug up and then a box of candy outside of the hospital.

Grampa sees the live footage of Petey from the interview being conducted in Petey’s house and laboratory. Grampa sees Living Spray and Cannery Grow in the background of the shot, and he and Big Jim go there.

Petey takes Sarah and the camera crew (with Li’l Petey and Molly in tow) to the sites of his childhood and young adulthood. He was imprisoned for a time and then was driven back to a life of crime by judgmental and hateful community members who refused to give him a second chance. He was inspired to turn away from his life of crime when he cloned himself to create his son, Li’l Petey. Petey also brings Sarah to the Happy Home Shelter, where he lived with his mom after his dad (Grampa) left them. Petey reflects that his mother was always positive and loving despite life’s hardships. Petey draws on this love in deciding to stop being a criminal and become a loving parent instead.

Grampa and Big Jim, who have entered Petey’s now empty house, go to his laboratory. Grampa slips on the sippy cups that were left at the top of the stairs and falls down the stairs. As he falls, he destroys the cardboard robot disguise; Big Jim realizes that it is Grampa. Grampa accidentally sprays the sippy cups with Living Spray as Big Jim tries to wrestle the can out of his hand. Now alive, the Sippy Cups grab the Cannery Grow, and Petey’s house is destroyed as the enormous cups grow and then eat Grampa and Big Jim (who float in the apple juice inside one of the giant cups).

The Sippy Cups set off across town. They grab Sarah, the cameraman, Petey, and Li’l Petey just as Sarah is concluding her interview. Molly escapes and goes back to the ruins of Petey’s house. She finds a meerkat machine in the destroyed lab and puts it on, becoming Mecha Molly.

Meanwhile, Chief and Dog Man set out to help. Chief goes to evacuate the hospital, which one of the Sippy Cups is attacking. He and Nurse Lady have to jump from a window; Dog Man throws them an umbrella, and they float to safety, kissing on the way down. Dog Man attacks one of the Sippy Cups in his Cone of Destiny machinery suit, but it ingests him, and the malic acid of the juice destroys the suit.  

Molly returns as Mecha Molly and shreds the Sippy Cups to pieces. The freed group members are taken aback by the violence, but Molly is nonchalant. Petey, Li’l Petey, and Molly return to Petey’s home. Dog Man rolls the pieces of 80-HD, who came apart in the malic acid of the apple juice inside the Sippy Cup, home to be fixed by Li’l Petey. Petey discovers that his house has been destroyed. Molly asks if she can keep the meerkat machine; Petey sarcastically tells her to please take his last possession. Missing his tone, Molly thanks him and leaves. Petey is devastated at their destroyed home, but Li’l Petey reminds him that love is the most important thing. They find Petey’s mom’s ukulele, which she used to play to young Petey, in the wreckage of the house, and Petey plays it for Li’l Petey. Petey and Li’l Petey embrace and then go to Dog Man’s house, where they will stay until their home is rebuilt.