No Clue (2013) on Netflix

Plot summary

Leo Falloon sells novelty advertising, and his office sits across the hall from the office of a real private detective. Kyra bursts into his office by mistake, believing he is that detective, and hires him to find her missing brother, Milles Severeign. Leo is a clumsy, middle-aged salesman, and he is so spellbound by her that he says nothing about the error. He poses as a private investigator and takes the case. The job pulls him into a tangled scheme of fraud involving computer game companies chasing high profits, and it embroils him in a risky murder mystery that deepens.