On The Last Ship Season 1 Episode 9, Rachel begins the human trials of her prototype vaccine.

Six brave volunteers are injected with not only the vaccine but the virus in order to confirm the success of her hard work.

Naturally, things don't go according to plan as the virus has muted causing severe symptoms Rachel is unfamiliar with.

With lives on the line, Rachel and her team struggle for answers. Why did it work on the monkey and not now?

Did you miss "Trials"? It's probably the most important episode of the season. Luckily you can watch The Last Ship online via TV Fanatic.