does this follow an actual story line or is just slice of life?

Both! The start is kind of a slice-of-life, but around chapter 18 the story picks up and things start to get serious, the artist keeps exploring their past and emotions and how it affects their quality of life in the present. It's a deep story but it also has a goofy sense of humour, its kind of "No Home" in a way. The artstyle and expressions are silly but the story itself has a lot of heart in it