Bert, in soccer gear, asks Ernie why he is wearing his ice hockey outfit, since they are about to be going to a soccer match. Ernie replies that there can only be one answer to that: they will now be going to an ice hockey match, and much to Bert's dismay, he'll have to change clothes. (First: Folge 2375)
Rumpel is putting the final touches on the new machine that he has built after the blue print his great great grandfather, Grouch Onardo created. Pferd comes by and asks about the machine, to which Rumpel tells him that it's a doubling machine and that he wants to be left in peace so he can test the machine; Pferd decides to hide nearby. Rumpel puts a screw into the machine and sets it to "two copies" and out of the machine come two screws. Rumpel is delighted that now he can have twice as much junk. He leaves Karl Heinz at the funnel for the machine to go and fetch more junk.
Pferd thinks it looks promising and wonders if it will work with carrots. He sets the carrot on the edge of the machine's funnel, sets the handle to "two copies" and the machine starts. However, Pferd remembers that he did not put the carrot into the funnel and as he turns to the funnel he knocks Karl Heinz right into it, resulting in two identical copies of Karl Heinz resurfacing. Pferd can't figure out which brush is the real Karl Heinz, and decides to call Wolle for help. Wolle arrives quickly and after understanding the problem, he declares it a job for detective Wolle.
Detective Wolle can't tell which one's the original Karl Heinz, so he decides to ask them. Unfortunately, he doesn't get an answer from the inanimate objects. Then Pferd notices that Rumpel is on his way back, so they try to hide, along with the two copies of Karl Heinz. Rumpel quickly notices them and asks what they were doing. Neither one can answer, as both have a brush in their mouths. Rumpel notices that Karl Heinz is missing, and goes on a search for him.
Wolle gets a new idea, Rumpel will surely be able to identify the original Karl Heinz; however, Pferd is worried that the grouch will get angry. Just as Rumpel is searching closer by the machine, Wolle and Pferd split up, each taking a Karl Heinz. Wolle places the one he has on the funnel just as Rumpel returns. The grouch is happy to see Karl Heinz on the funnel, but notices the carrot on the funnel as well. Wolle can't explain it. Pferd turns around to see whats going on and Rumpel is surprised that Karl Heinz has a visitor that he hadn't told Rumpel about. Pferd admits that it's Karl Heinz's doppelganger. The happy grouch agrees for the doppelganger to stay, and as Wolle declares the case closed, Rumpel multiplies hundreds of carrots as a thank you for Pferd.
Lilly and Sofie, a pair of twins, talk about their differences.
Ernie wants to talk about big and small, so naturally he recruits Bert to help. He suits him up with a hat too big for his head while Ernie wears one that's too small. Ernie picks up a tiny box and asks Bert to get the one off-screen which is so big that Bert has trouble carrying it. Finally, Bert wants to demonstrate small this time, so Ernie gives him a bite-sized cookie, only to walk away with an enormous cookie for himself.
The Wörterfee asks Wolf vom Wörtersee for his help, it seems that the lake is loosing water, for the "lake stopper" is missing. Wolf tries to figure out what a stopper is. He finds a weird round thing on a chain near the lake, but since he doesn't know what it is, he just throws it away. With the help of his friends he tries to figure out how to stop the water. He decides that the right thing to do is to build a submarine. As the submarine is finished, he once again notices the weird round thing on a chain, and decides that it would make a great amulet for a submarine captain. However as he is about to put the submarine in the water, it falls a part. The Wörterfee re-appears and notices the stopper around Wolfs neck and thanks him for saving the lake.