Underdog
In the Capital City Town Hall, a beagle on the police bomb squad sets off a false alarm. After being shunned by his fellow police canines, the beagle leaves in shame and is abducted off the street by Cad, who takes him to Simon Barsinister's lab. Bitter his proposal for genetic experimentation was declined, Simon plans to prove the mayor wrong by testing his new serum on the beagle. Underdog escapes and runs amok in the lab, causing a fire and becoming exposed to various chemicals, which modify his DNA and give him superpowers.
After his escape, the beagle avoids an encounter with a Rottweiler named Riff Raff and his lackeys. Dan Unger strikes the beagle with his car, but, thanks to the serum, the beagle is unharmed. Dan takes him home and names him Shoeshine after the dog licks his shoes. Dan's son, Jack, becomes jealous of Shoeshine's attention. Dan retired from the police to spend more time with Jack after his wife's death but still seems busy. Jack leaves for school and Dan for work, leaving Shoeshine at the house alone, where he, still unaware of his new powers, accidentally makes a very large mess. After coming home, Jack complains as he cleans up, and Shoeshine shocks both of them by claiming it was an accident. Jack initially runs away, but after they reach a park, Jack and Shoeshine talk and bond over their respective attraction to Molly and Polly, Jack's friend and her dog. After the girls leave, Jack and Shoeshine test his powers.
When Molly and Polly are mugged, Shoeshine rushes to their aid, discovering he can fly. After discreetly rescuing them, Shoeshine returns home with Jack, making Jack promise to never reveal his powers. Cad shows up at the door with posters of Shoeshine, but Jack fools him into leaving just before Dan comes home to discover the mess. Meanwhile, Simon and Cad find a new lair beneath the city, then plan a robbery to fund rebuilding Simon's lab. Seeing Cad's heist on the news, Jack convinces Shoeshine to intervene. Shoeshine disguises himself and saves the hostages, but Cad escapes. Shoeshine adopts the alias Underdog and becomes the city's resident superhero, donning a red sweater and blue cape as his disguise.
Simon repeatedly fails to recreate his serum and sends Cad to obtain a sample of Shoeshine's DNA. Shoeshine is rebuffed by Polly but gets a date with her as Underdog. Cad fails to capture Underdog but obtains his collar, which contains Underdog's name and address. Barsinister and Cad kidnap Dan and force him to call Shoeshine for help. Shoeshine and Jack attempt a rescue, but Barsinister uses both Jack and Dan as hostages to convince Shoeshine to give up his DNA. Barsinister synthesizes Underdog's superpowers into pills, forces Shoeshine to take a power-nullifying antidote pill, and feeds the super pills to three trained German Shepherds. He and Cad leave the family trapped in the sewers, but Dan's police experience allows him to free everyone. They pursue Barsinister with a hypodermic filled with the antidote.
At the city hall, Barsinister takes the mayor hostage and instructs Cad to attach a bomb rigged with a mind control serum to the roof; Molly and Polly follow Cad. Shoeshine smells the bomb and, conquering his self-doubt, enters the building despite having lost his powers. During a scuffle with Barsinister, Shoeshine accidentally rips open Barsinister's pocket and swallows a pill. With his powers restored, Shoeshine temporarily incapacitates the German Shepherds after he hears Molly and Polly cry for help, but Barsinister eats a pill and distracts Shoeshine by tossing a Frisbee. When the German Shepherds recover, Shoeshine convinces them to turn on Barsinister, who has not treated them well. While they restrain Barsinister, Shoeshine disarms the bomb, saving Molly and Polly. Dan injects Barsinister with the antidote, and Shoeshine, dressed now as Underdog, buries the bomb in the park. He is caught in the explosion and thought dead, but a mournful crowd is overjoyed when he revives. Dan is reinstated as a police officer, Barsinister and Cad go to jail, and Shoeshine returns to protecting Capital City as Underdog.
psychedelic