Corona and her classmates learn a bit about lightning. Some people have a good time, others don't. The title doesn't appear to be a well-known saying, so there's a chance it's related to a film Man Who Causes a Storm. If so, there could be some pun on “chestnut” in the title that I can't see.
Another hypothesis is that it's a reference to the term “lightning crystal” from various RPG games (with “crystal” transliterated from English) to クリスタル, then abbreviated to クリ, which is exactly the way “chestnut” is written in the title).