This episode page has been compiled from the episode description at the NDR website.
Finchen and Nils are watching the glowworms and they are both impressed by them. Finchen wonders why glowworms glow, Nils are not sure why but he does have a book on the subject that he will go and find. Just after Nils leaves Finchen hears someone complaining nearby, it turns out to be a glowworm by the name Gerlis, who have crashed and her lamp are so dirty that she can't glow. Finchen offers to help Gerlis clean the lamp.
Nils has found the book, and starts to read outside the store, however he can't see anything in the book, so he decides to fetch a flashlight.
Finchen has cleaned up the lamp, Gerlis testing it right away, and it works. Finchen asks Gerlis if she can find her friends again, Gerlis says that's not a problem she will use her glow to find them. Finchen realizes that it means that glow worms use the glow to find each other. Gerlis starts to signal her friends, however there's no response.
Gerlis is sad that she didn't get a response from her glow. Finchen suggest that they sing a glowworm song that will surely help, and they begin to sing. At the end of the song they notice many glows on the sky, Gerlis thanks Finchen and joins her friends. Nils arrives and says he has the answer in the book and as he begins to read Finchen says that glowworms glow to find their friends, he tells Nils that her glowworm friend Gerlis told her all about glowworms.
Kermit intends to talk about light and dark, so he turns his living room lamp off. Grover enters, leaving the door open so that the room doesn't stay dark. He tries to help by eliminating all light in the room so neither of them can see.
The Twiddlebugs don't understand why they are getting all wet, while Mommy Twiddlebug isn't. They soon learn it's because she's inside the house. After they all huddle inside, Ernie finishes watering his plants.