This story IS BONKERS. This is a true story based on what now is considered by far the biggest serial killer to ever live in the United States history. And you have never heard his name.
This movie tells the story of a male nurse who decides that he was going to inject stuff into peoples IV bags with a syringe, that messes with their blood flow and kills them. Doing it this way makes it look like a complete accident. He travels around from hospital to hospital for decades. Until one hospital nurse (Jessica Chastain) starts to really grow suspicious of these deaths. They should not be happening. She is really good at her job and something is not adding up. So she investigates.
The rest is a thrilling ride on her adventure to figure out what is going on and eventually catch the biggest serial killer to ever live. Just a fucking crazy story and movie did it really well. This was a EXCELLENT FREAKING FILM. Watch it ASAP. That is a review.