Well, it could be that there's a misunderstanding. Hermione is a very intelligent and passionate character. She might have misinterpreted something that happened at the Burrow. For example, a comment made by Mrs. Weasley that Hermione took the wrong way. It could have been something as simple as a suggestion about her relationship with Ron that Hermione thought was over - stepping. So, in her characteristic strong - willed way, she storms out, leaving everyone at the Burrow a bit shocked and setting the stage for a story of reconciliation or further conflict.
Ron would most likely be one of the main characters. Since Hermione and Ron have a complex relationship, his actions or words could be the reason for her storming out. Also, the Weasley family as a whole could be important characters. Mrs. Weasley, for instance, with her motherly but sometimes overbearing nature, might play a role in the events that lead to Hermione's departure.
Well, it could be about their simple daily life at the Burrow. Maybe they are helping Mrs. Weasley with the housework, and there are some cute and funny moments between them, like Ron accidentally messing up a spell while trying to assist Hermione in cleaning the dishes.
Another possibility is that they are involved in some sort of mystery or adventure at the Burrow. There could be a strange magical object hidden there that they discover together. They then have to figure out what it is and how to deal with it, using Hermione's knowledge and Fred's quick - thinking and daring nature.
In such a fanfiction, one possibility is that Hermione leaves the Burrow to bring Harry some important information. Maybe she's discovered a new lead on the Horcruxes. She could be racing against time to reach Harry before Voldemort's forces find out about it too.
The 'Hermione Heals at the Burrow' fanfiction probably has a story full of care and recovery. Hermione may have faced some difficult situation before arriving at the Burrow. Once there, the family would rally around her. Ginny could be her confidante, sharing secrets and helping her deal with any emotional turmoil. The twins might use their humor to cheer her up. And all the while, Hermione is slowly but surely getting back to her strong self with the love and support of the Burrow's inhabitants.
In this fanfiction, the entire Weasley family could be involved in helping Hermione. Ginny, being Hermione's friend, would surely be there for her. They could talk about their experiences and Ginny could give Hermione the emotional support she needs. The Weasley boys, too. Fred and George might use their unique brand of magic to bring some cheer to Hermione's recovery. Ron, of course, would be by her side as well, perhaps feeling guilty if he thinks he had a part in her getting hurt.
One possible plot could be that Harry discovers he is pregnant while staying at the Burrow. There could be a lot of chaos as the Weasley family tries to adjust to this unexpected situation. Maybe Harry has to deal with his own fears and insecurities while also getting support from the Weasleys, especially Molly who could be very motherly towards him during this time.
Well, it could be about Percy discovering new powers related to the God of Storms. Maybe he has to face a powerful enemy that can control the weather in a menacing way. And he has to use his newfound storm - based powers to defeat it.
It's difficult to say if it's popular. Just from the title, it doesn't seem to be a widely known one that comes up in general discussions about popular fanfictions. However, it could be very popular within a niche group of fans who are interested in the particular characters and the setting of the Burrow, but without looking at things like views, reviews, and rankings on fanfiction sites, we can't be sure.
Well, it could be about Harry using his magic skills and knowledge from Hogwarts to improve the Burrow's security. Maybe he installs some advanced protective spells to keep out Death Eaters or other threats.