This is a rom-com about two teens who played together as kids growing up in the same apartment complex, but who grew apart over the years. Now when one's family is going away the parents arrange for their son to stay with the other boy's family for a few weeks; to the protest of both.
It is mostly told from the viewpoint of the heavy-set guy who struggles with body image through much of the movie. He struggled mentally with his appearance, but was also kind of a jerk and mean-spirited at times. While he does work on accepting the way he looks, he never does anything about his attitude. This is in contrast to the other main guy of the story, who is relatively relaxed and more of a warm person.

The movie does try to emphasize comedy, and it does have some of that, but it's more of a subtle humor that runs throughout the movie rather than a laugh out loud type of humor.
I won't give away the ending, but it would be considered a happy ending for sure, although the guys had to go through a few hurdles to get there.