The answer to your question is the title of the poem.
Answer:
The line 'So Eden sank to grief' is an allusion, or literary reference, to the Biblical story about The Garden of Eden, a perfect paradise until Eve ate from the Tree of Knowledge. By making this reference, Frost is implying that the idea nothing good can last is an old one; it's part of our human experience.
This was Greg and Rowley's Holiday Bazaar they made in Cabin Fever. They advertised it through their newspaper, The Neighbourhood Tattler.
When writing a summary, remember that it should be in the form of a paragraph. A summary begins with an introductory sentence that states the text's title, author and main point of the text as you see it. A summary is written in your own words. A summary contains only the ideas of the original text.
