This is the story of a man who failed to achieve his dreams as a Tokyo comedic musician and decides to back to his hometown to start over again at his family's traditional sweets shop only to find a little girl has taken his place as the family's successor. Said girl was left there in the care of his family by her father for reasons only known to him and thankfully the girl and the family warmed up to each other quite well. The foolish prodigal son isn't exactly welcomed back with greatest reception so he'll have to do his best to earn his place back in the family trade and in their hearts.
I do wonder if the synopsis gave the right idea as to what kind of story this is but if it's not clear allow me to amend that by clarifying that this is a fairly lighthearted tale of healing and growth for the ensemble cast in the story. I say fairly because there obviously had to be hurts in there that necessitated the healing and surprisingly enough, it's not centered so much on the healing of the protagonist but pn the people around him. He actually serves as the agent of healing for the most of the cast and he does it like the big goof he is. The other star of the story is the strongheaded little girl that's doing her best to make the best of her situation in earnest. Her parents haven't exactly done right by her but she still yearns for them and is haunted by how she was left behind by them. Where his arc is to make a fulfilling life for himself, hers is to move on and accept the blessings she does have in her life.
You can probably deduce that the main draw of this series is its character work. What story that's there comes from the characters and their issues and it's told with a light, crisp artstyle that sells the hopeful tone the characters work towards to. Every character is their own person with their own motivations, quirks and dreams and thats makes for a wonderful read about living. The setting places the family sweets shop at the center of their universe and I'd be amiss if I didn't mention that it does go in depth enough into the subject to make my mouth water at some of the black and white treats that get shown. It's featured prominently enough to serve as an advertisement for tourists and explored enough to get a decent idea of the effort that gets put into making the things. I'm certainly going to make it my mission to get my fill of sweets next time I make a trip to Japan. The main plot with the girl's abandonment moves along at decent enough pace but it's less a main plot and more like one of the bigger character arcs in a basket filled with them. Despite the slow, sporadic progression of this main plotline I never felt like the story ever dragged its feet as like I said, this really is more a story of the lives of a whole family than the story of the leads.
The closest parallel that comes to mind is Barakamon and to use it as a comparison, Deaimon is a much sweeter and more sincere story of a little girl finding a father in her life. As far as I can tell no one's picked this up and this is supposed to be a rather popular work that won awards. I recall seeing it on a poll for works that should get an anime adaptation some time near the end of last year so I do hope we'll see one soon. If you can read Japanese I can't recommend this enough, if you're looking for a project then I encourage you to pick this up and if neither are you but peckish for something whole and hearty, you should hunt down the craftsmen that can prep it up for you.
All in all, Deaimon is the sweet treat you should be munching down on.