Jimmy Jack Wild is wrongly ejected from his school band after tripping, and his flute suddenly transforms into a magical talking golden flute named Freddy Don Messick. The two embark on a journey to a fantastic place called Living Island, where everything around them is alive and capable of thought. There, they Befriend the island’s residents, who are led by the cheerful and protective Mayor H.R. Pufnstuf Allan Melvin. But the peace is short-lived: the conniving Witchiepoo Billie Hayes schemes to steal Freddy the Flute so she can impress the visiting Witches’ Council and the Boss Witch, hoping to snag the Witch of the Year Award.
Witchiepoo hatches a plan to abduct Freddy by disguising herself as a charming, elegant dance instructor. With the flute in her grasp, she hopes to elevate her standing among the witches. Jimmy and the townsfolk quickly realize Freddy is in danger, so they seek help from Dr. Blinky Johnny Silver, a quirky resident whose odd ideas might hold the key to saving Freddy. The group soon devises a clever rescue operation inspired by a talking chimney’s odd advice. They decide to masquerade as firefighters, while Googy Gopher Billy Barty digs a tunnel toward Witchiepoo’s castle, and they stage a dramatic fake fire that distracts the witches long enough to mount a rescue.
Their clever plan initially succeeds, and the team celebrates recovering Freddy. A mail carrier pelican named Orville Pelican arrives with news that hints at a way off the island. The plan to leave aboard Orville’s beak seems promising, but the added weight proves too much, and the makeshift ride crashes into a rock, foiling their attempt to escape.
Witchiepoo, not finished, gets a call from Boss Witch, who is coming to Witchiepoo’s castle for a witch convention and wants to see Freddy. In classic comic mayhem, Witchiepoo blows up Pufnstuf’s town with a doomsday-style assault and uses her power to shrink and imprison the islanders inside her fortress. Jimmy, once again determined to save his friends, decides to infiltrate the castle by posing as a witch. He is discovered during the rescue attempt, and Freddy is taken again while Jimmy and the others are locked in a dungeon with the island’s residents.
In a pivotal turn, Googy Gopher digs into the dungeon to break everyone out, though Pufnstuf remains in danger of becoming a cook’s meal. The group narrowly escapes the castle with Freddy and Pufnstuf, but Boss Witch brokers a deal: Witchiepoo will be crowned Witch of the Year if she relinquishes Freddy. Witchiepoo agrees, hoping to secure her victory while the others regroup.
Back at Dr. Blinky’s place, the team uncovers a curious riddle: the only thing that truly scares witches is a good fairy angel. Embracing this idea, they dress as white, benevolent fairies and storm the castle to confront the witches. The bold ruse works, and they scare off the Witches’ Council, freeing Freddy and Pufnstuf from captivity.
Witchiepoo quickly realizes she’s been outmaneuvered; she races to warn Boss Witch, and her minion Orson Joy Campbell nearly causes chaos with a doomsday bomb. In a fateful mishap, Orson drops the bomb inside their own contraption while trying to take the wheel, causing the Vroom Broom to explode and sending Witchiepoo and Orson tumbling to the ground.
With the island safe for now, Jimmy and his friends reflect on their wild adventure. The curtain closes on a joyful musical number, as Pufnstuf sums up the spirit of the tale:
> When good friends pull together, they can do anything.
