本作品讲述了在警察“机动搜查队”，机动能力和运动神经首屈一指、但却没有刑事搜查经验也缺乏刑警常识的伊吹蓝（绫野刚 饰），观察和社交能力突出,但却不信任自己和别人的理性的刑警、志摩一未（星野源 饰），主角二人以24小时的时限内破案为目标的故事。 标题中的“MIU”是Mobile Investigative Unit（机动搜查队）的首字母，“404”是两人饰演机动搜查队员的呼叫信号。
In the second series, Adam goes on a date with a girl who smells like Mum, Jonny starts going out with a much older woman, Mum is forced out of the house by a mouse, Dad starts drying fish in the downstairs cupboard, neighbour Jim makes a birthday cake for his dog Wilson, Grandma gets a new boyfriend who no one likes, and we meet Dad's mother - 'Horrible Grandma'.
