"You are... the absolute WORST human being on Earth!"
— Timmy Turner
"Thank you! Now... START SHREDDING!"
— Vicky, causing the avalanche
Snow Bound is the thirty-first and final episode of Season 3.
Mr. Turner brings Timmy and Vicky to the ski resort. He hopes to save Mrs. Turner from the Abominable Snowman, which he saw on television. Vicky is snowboarding there, and her "snowboard" is Timmy. The problem is: her loud shout causes an avalanche, that traps them in a cold cave. To his surprise, Vicky's anger cools down and she becomes nice. How will Timmy get out when his fairy godparents are frozen? To make matters worse the Abominable Snowman comes into the cave and corners them!
Mr. Turner looks worried when he phones his wife. She is at the ski lodge relaxing, but she lies to him by telling him she is only there to take care of her (non-existent) sick "Aunt Denise". Mrs. Turner is spending quality time together with the mothers of Timmy's friends: A.J.'s Mom, Elmer's Mom, and Sanjay's Mom. Mr. Turner is relieved for the moment, until a news broadcast warns skiers than an Abominable Snowman is on the loose. This is enough to spring Mr. Turner into action, he grabs Timmy and starts heading toward the ski resort. On the way, he picks up Vicky so that she can watch over Timmy. Before taking off to look for the Abominable Snowman, Mr. Turner gives Vicky a handful of cash so she can go snowboarding.
At the top of a huge mountain, Vicky begins snowboarding: using Timmy as the snowboard. At the ski resort, Mr. Turner stalks what he believes is the snowman, barging in on his wife who was relaxing in a hot tub. Mrs. Turner believes she has been caught, but her husband thought the hot tub was filled with her tears from her sadness over her aunt. Mr. Turner asks where her aunt is and she tells him that she is hiding from the Abominable Snowman, who is terrorizing the 24th floor of the resort. When Mr. Turner runs out, the other moms emerge from hidden underneath the water, gasping for air. Mr. Turner runs to the roof of the building and screams in anguish, believing the snowman ate the whole floor.
Meanwhile, Vicky is shredding her Timmy-snowboard down the side of the mountain. Timmy calls her the worst human on Earth which Vicky takes as a compliment. She yells "Start Shredding" which causes an avalanche. Timmy and Vicky tumble into a cave, and the snow buries them in. Timmy is not worried at first, until he realizes that his Fairy Godparents are frozen in the ice of the fish bowl like Fairy God-sicles.
Timmy makes fire but even the fire freezes. Timmy and Vicky argue as they shiver in the cold. Vicky blames Timmy for them being trapped, but Timmy says that everything bad that ever happens is caused by Vicky. She breaks down and cries as she apologizes to Timmy, saying that she doesn't mean to be bad all the time, she just is. Timmy starts to feel bad and suggests they hug to share body warmth, which Vicky immediately obliges. At the ski resort, Mr. Turner notices "yeti droppings" (ice cubes) on the ground and starts to track the Abominable Snowman before he slips on one of the ice cubes and falls down a flight of stairs.
Back inside the cave, Vicky is lying on an ice sculpture that looks like a psychiatric chair, confessing a painful childhood memory to Timmy. Vicky explains that when she was eight, her mother told her that her pet turtle ran away while she was at summer camp, but Vicky knew that was a lie since turtles can't run. Suddenly, a giant, white furry creature bursts into the cave. It is the Abominable Snowman. Vicky and Timmy panic and run away, until they find a pile of hot pizza's hidden in the cave. The snowman corners them, but Vicky defends Timmy and prepares to fight off the creature. Timmy sticks his tongue to the frozen fishbowl and then tosses the fishbowl up into a hole on the top of the cave, allowing him to escape. Timmy uses the sunlight to thaw his godparent's, and tells them they have to save Vicky. Cosmo doesn't believe that Timmy would ever want to save Vicky and thinks they have been unfrozen in a strange twisted future. Back inside the cave, Vicky is trying to fight off the Abominable Snowman with frozen wads of cash, when Timmy bursts in on a drill-machine and shoots the snowman with a snowball gun. He gives Vicky a snowboard, and together they shred down the mountain. Vicky compliments the magical snowboards, which Timmy claims he got off the internet. They see the Abominable Snowman chasing after them, snowboarding on a pizza box.
At the ski resort, Mrs. Turner complains that despite an avalanche they still should have received their pizza hours ago. Vicky and Timmy burst in through the wall, and the abominable snowman is not far behind them. The snowman delivers the pizza and rips off his furry white coat, revealing he is actually the Abdominal Snowman, a muscular looking man with blond hair. He was trying to reveal himself to Vicky but he didn't want the pizzas to get cold by taking off his coat. Mr. Turner bursts in tries to attack him but bounces harmlessly off his "rock hard abs". The snowman points to his ad, the news "warning" Mr. Turner saw earlier, which was in its entire length an ad for pizza delivery.
Sanjay's mother puts on some music and everyone begins to dance. Wanda comments to Timmy that he is now friends with Vicky, until she comes over and smashes a pizza box over his head. Vicky is upset at Timmy that he prevent her from getting with the Abdominal Snowman. She screams at Timmy again, causing another avalanche. The snow piles in through the door of the resort, and Vicky is covered. Mr. Turner mistakes her for the real abominable snowman and chases after her with a snow shovel. Everyone is safe, Vicky hates Timmy again, and Cosmo is still the most oblivious idiot on the face of the Earth: Everything is back to normal as the episode ends.