When a top notch agent finds a drug that is killing people, she enlists the help of her lazy, post war, pension living boyfriend to aid her in finding out how to stop the drug before an entire city is wiped out.

The agency for me isn't the issue. What forces her outside the agency is the story. Is it corrupt, are people in the agency involved or has she been framed?

I'm doing my research on that right now, so I really don't know. Ordinarily DEA would handle these situations in real life, most likely along with hazmat units to make sure the stuff is safe, but I'm trying to scope opportunities for new ideas. FBI is used way too much for me and M:I6 would infer that the movie takes place in Great Britain, even thought leaves a few pathways as well to explore. If all else fails for me, I'll make one up.

The agent of what? The agent of s.h.i.e.l.d.? Agent to the stars? FBI agent? M:i6 agent?

It doesn't take that many words to say CIA agent or DEA agent and give the reader a little more clarity.