When people finish their day and hurry home, my day begins. My restaurant is open from midnight to seven in the morning. They call it "Midnight Dinner". That's all I have on my menu. But I do whatever the client asks for as long as I have the ingredients for it. That is my policy. Do I even have clients? More than you would expect.
"The Master", the main protagonist of the show, is the owner, chef and bartender, and operator of the representative restaurant. Although he has a very limited menu (which includes only tonjiru, sake, beer and shōchū), he always offers to produce any dish the customer might want, as long as he is available. resources. Master refused to cook anything that was beyond his skill or was too complicated. Sometimes, customers contribute ingredients, especially if they are unusual or a very specific craving. The restaurant is frequented by customers, from salaried workers to yakuza and prostitutes, all of whom get along very well; there was only occasional conflict between characters while in the restaurant.
In general, each episode refers to a drama that focuses on a particular customer. The plot introduces the episode's characters, often using famous archetypes and tropes, before detailing their individual challenges. Master, although often quiet, but gave help and advice. The plot often offers a philosophical lesson about life as part of the story, whether simple or complex. The stories often have a cheerful tone, but some plunge into more dramatic territory with melancholy determination. Most episodes focus on a particular Japanese dish, usually the character's favorite meal the episode is about. The dish was also involved in the story in some way, and the episode ended with Master briefly presenting the recipe while a character in the episode gave direct verbal instructions to the audience. Teacher also occasionally breaks down the fourth wall, to speak with viewers (eg in a TV series, to announce an upcoming movie or to announce a partial end). The Master cooks everything himself, only asking for help if he knows he can't do something or if he loses the ability to work (ex: In the first movie, the Master gets a homeless girl played by Tabe Mikako after he got injured). While the characters are mostly transitions and mostly viewed in their own episodes, some are often seen as supporting characters or cameos in another episode or two. Some characters are familiar customers of the restaurant and appear regularly.  Some stories use overtones of magical realism, including supernatural elements, while others use montage and elapsed time to tell the full story of the character.
Master (Kaoru Kobayashi)
Master is the only character to appear in every episode. He is a somewhat mysterious figure; well-regarded for his cooking prowess, his background is largely unknown. He has a visible scar down the left side of his face, implied in one episode to be from a sword attack in a past life; however, its origin is never properly explained. Master's actual name is never given, and all characters simply refer to him as "Master". He is generally sympathetic, despite the various problems his customers have, though he never gets too involved in their affairs. Generally, he is not directly involved in outside scenes with them, interacting only when they come to his diner. His main ways of assisting people are to bring them comfort by making food, and to provide advice. His character is similar to a bartender in that he functions as an adviser/therapist as the characters project their insecurities or issues onto him, or discuss and mull over their problems. Most of the time, he is seen cooking, washing dishes, or having a cigarette either in the diner or on the small balcony of his upstairs apartment. He has a few unwritten rules for the customers: There is a three-drink limit per person, as he does not run a bar; there is a three-toothpick limit as well (Season 3, Ep 4); and any arguments must be taken outside.
Tadashi/Mr. Chu (Mansaku Fuwa [ja])
Frequently addressed as "Chu-san", he is the character in the show that most frequently appears (apart from Master). He is a cheerful older man, who is always seen wearing a blue cap. He occasionally offers advice and harmless banter to the other customers in the diner. Generally, the stories do not involve him, he instead sits in the diner to pass comment and reminisce about his youth.
Kosuzu (Toshiki Ayata)
A homosexual cross dresser who owns a successful restaurant/gay bar in the same neighborhood as the diner. Kosuzu is often seen dressed in eccentric outfits while at the same time chastising others for their appearance or behavior. He enjoys gossiping but is quick to defend his friends at the diner and his restaurant employees from scrutiny. He forms an unlikely friendship with Ryu.
Ryu Kenzaki (Yutaka Matsushige)
Yakuza boss Ryu stops by the diner randomly, always asking for Master to prepare dishes from his childhood. Ryu's storylines largely take place outside the diner and despite being a member of the Yakuza, the other customers worry about his well-being. He forms an unlikely friendship with Kosuzu. He has a turbulent past with Detective Noguchi, with whom he was a schoolmate and a member of the same baseball team.
Detective Noguchi (Ken Mitsuishi)
A diligent police detective, who visits the diner when he is on a case or to indulge in a specific craving. A baseball player in high school, Noguchi enjoys eating food from his youth that remind him of traveling during baseball tournaments. He has a turbulent past with Ryu Kenzaki, with whom he was a schoolmate and a member of the same baseball team.
Komichi (Shohei Uno)
An amateur photographer who takes photographs of the diner customers and occasionally has exhibitions in a local gallery. He is a bit clueless when it comes to proper etiquette and he is often distracted by other characters so that he does not embarrass himself.
The Ochazuke Sisters (Risa Sudo, Asako Kobayashi, Nahoko Yoshimito)
Collectively called "The Ochazuke Sisters" by Master and other customers, Miki, Rumi, and Kana are three office ladies who go to the diner after a long day of work to unwind and gossip. Like Tadashi, they are generally not involved in the drama and are among the most frequently recurring characters. With bowls of ochazuke in hand, they offer commentary on the drama, being generally sympathetic to the involved parties whilst complaining that they are still unmarried.
Kanemoto (Kiyofumi Kaneko)
A divorced alcoholic, Kanemoto works as a salaryman and comes to the diner because the other customers are the only people he enjoys interacting with. He is generally moody and carries a serious face, only becoming cheery when he gets to show off his intelligence or gets a new girlfriend
Katagiri (Joe Odagiri)
A mysterious patron, he always sits in the back-corner of the diner closest to Master's kitchen area. He drinks sake and is frequently seen playing with food (namely peanuts and egg shells) before arranging them in neat rows. Unlike the other customers, Katagiri dresses in traditional Japanese clothing and speaks in cryptic, philosophical statements that are left open to interpretation. He has a special relationship with Master, as he is the only person with whom Katagiri converses normally.
Kogure (Joe Odagiri)
Only appears in seasons 3, 4, and 5. He is a police officer who works in the neighborhood kōban with jurisdiction over the Master's diner as well as the neighboring shops and restaurants.