It is the sixty-third episode in the series.
After Hildy casts a spell on the 7D that turns them into mimes, Grumpy leads the group on a dangerous mission to retrieve their lost voices from the Cave of the Yeti.
Happy sings his way along a path as he encountered a nervous man hiding behind a rock. The man, who is the postal courier for Jollywood, is afraid of delivering a Jollygram addressed to Hildy Gloom. The Jollygram turns out to be a poem written by her husband Grim in celebration of their anniversary. Happy offers the courier to deliver it to the Glooms for him. Happy then sets the poem to music on his guitar having slightly disgusted by Grim's gloomy words describing the love of his life, he tweaked the words to make it peppy.
Later, Happy arrives at the Glooms' home. Hildy has been expecting something from Grim since it's their anniversary. They then encountered Happy at their doorstep with the Jollygram and he begins to sing to them his sunny, altered lyrics. This literally make the Glooms sick, and after Happy finishes the song, they become furious. Hildy then casts a spell making Happy unable to speak and sending his voice to an icy cave in Mount Jollywood. Another spell is cast to transform Happy into a mime!
Mime Happy runs back to the 7D's cottage and he first seek the help of Grumpy, but he doesn't understand what he's trying to do. The other dwarfs arrive and after translating from Dopey, they finally found out that Hildy turned Happy into a mime. The 7D walked over to the Glooms (while Grumpy hides behind a tree) and demand them to turn Happy back. Hildy refused, and now the 7D (sans Grumpy) have their voices sent to the icy cave and transformed into mimes!
Soon after, the Bing-Bong Bell is heard from Queen Delightful's castle, and the Queen is excited at the sight of the 6D as mimes. Grumpy tries to explain what happened to his pals, but Delightful already knew what Hildy done to them thanks to Happy's pantomiming. She called them to open a very secure safe on the wall of the Throne Room that can only be opened by each of the 7D's voices (by saying their names) on a microphone. Now she's worried that she won't have the safe opened at 12:30 pm for a special celebration because the 6D have lost their voices. Grumpy and the 6D now have to trek up Mount Jollywood to get their voices back.
While the mime dwarfs pantomiming their way up the mountain and the Glooms continue their anniversary, Lord Starchbottom has an idea to say the names of each of the 7D, though Delightful cautions him against it. After he says their names in a very bad impression of each, a mechanical hand with a hammer comes up from a floor and strikes him on his foot. This doesn't stop him, however: Starchbottom tries hard to get their voices right (including Dopey's whistling) and even dresses up as each of the 7D, but gets more punishment in forms of being squished by the safe's wall and two walls with springs from each direction, not to mention being hit in the nose with a hammer! The 7D finally reach the icy cave at the summit, and Grumpy hears their voices. But, as it turns out, the 7D's voices come from a family of yetis!
The yeti family, however, doesn't like having voices, so they along with the 7D went to the Glooms. At first Hildy believes that the yetis are another anniversary gift from Grim. But the yetis are there to confront the Glooms to have the voices return to the dwarfs, prompting them to flee from their home. Now that the 7D have their voices back and no longer mimes, they have the safe opened back at the castle. Inside the safe is simply a long bologna and cheese sandwich Delightful shares with the 7D! Then Starchy drops after getting so beat up.