Natsumi, who works in a cafe, loves lunchtime. In fact, nothing excites her more than walking down the street thinking where she'll eat lunch at.
One day, a guy by the name of Kennichiro suddenly interrupts Natsumi as she is savoring her favorite rice omelet. He pulls the now furious Natsumi out of the restaurant and begs her to come home with him so that he can introduce her to his family. He explains to her that his father is sick, and since leaving home two years ago after a big fight, the only way he can return home is if he has a fiancee with him.
Kennichiro's father and 3 brothers: Yujiro, Junzaburo, and Koshiro, run a restaurant called "Kitchen Macaroni." The only one in the family that doesn't work there is Kennichiro. Also working at the restaurant are Mamoru, a cook, and Minoru, an apprentice cook.
As Kennichiro and Natsumi approach the restaurant, Kennichiro asks Natsumi to go in alone and check out what is happening inside. Natsumi responds by reluctantly entering alone. As she takes a look around, she sees Koshiro talking to Tomato Shiomi, who works at the nearby grocery store called "Shiomi." Kennichiro's other brothers are working in the kitchen. Next she spots Kenzo, who according to Kennichiro is supposed to be ill. Naturally, Natsumi can't believe how irresponsible Kennichiro is for telling her such a thing. While she is thinking this, the omelet that she ordered arrives. She takes one bite out of it, and as she smiles, the next thing out of her mouth is, "delicious!" A short time after, Kennichiro walks into the restaurant, and his brother Yujiro grabs him and starts lecturing him for coming back. Natsumi breaks them apart, but senses Kennichiro isn't appreciated there.
This is the first day that Natsumi gets a real "taste" of "Kitchen Macaroni," and also Kennichiro's brothers, who are bent on serving delicious lunches to their customers.
カフェで働く麦田なつみ（竹内結子）が、一日で一番楽しみにしているのが休憩時間のランチタイム。「今日はどこで何を食べようか？」なんて考えながら、街に繰り出すのが嬉しくて仕方がない。
そんなある日、なつみの“大切な時間”に割り込んで来た男がいた。鍋島健一郎（堤真一）だ。なんと、ランチタイムに･･･しかも、大好きなオムライスを食べている最中に、健一郎は強引になつみを店から連れ出してしまった。怒るなつみに、健一郎は実家で家族に紹介するから一緒に帰って欲しいと頼む。父親が倒れてしまったのだという。しかも実は２年前喧嘩して家を飛び出したから、婚約者でも連れていないと帰れないというのだ。健一郎の実家は洋食屋『キッチンマカロニ』だ。
鍋島家は、父親の権造（若林豪）を家長に、健一郎、勇二郎（江口洋介）、純三郎（妻夫木聡）、光四郎（山下智久）の4人兄弟。『キッチンマカロニ』は、健一郎を除いた家族と見習いコックの牛島ミノル（山田孝之）、通いのコックの川端守（田窪一世）で経営されていた。店の前まで来ると、健一郎はなつみに先に行って家族の様子を見てきて欲しいと頼む。渋々、店に入ったなつみ。近所の八百屋『しおみ』の娘、塩見トマト（伊東美咲）と話す光四郎や厨房で働く家族を見ていると、倒れたはずの権造の姿も･･･。健一郎のいい加減な話にあきれるなつみ。オーダーしたオムライスが運ばれてくる。一口食べると･･･。「おいしい！！」となつみは満面の笑み。
そこに、のこのこ健一郎が現れた。勇二郎が、何しに帰ってきたんだとばかりに健一郎につかみかかる。なつみ
