After celebrating her best friend's wedding, FBI agent Emma Griffin and the gang are looking forward to a much-needed vacation.
They hop onboard a cruise ship excited for the many excursions and adventures.
But as time progresses rumors and murmurs circulate about a woman that might have gone overboard.
A strange woman that Emma had just spoken to a few days prior.
The search for the missing woman hits dead ends, prompting Emma to involve herself and look into the woman's cabin, finding only more questions.

The crew members appear to be on edge, and it seems as though they have been silenced.
When more odd things occur and flowers start to appear everywhere.
It seems that it's only a matter of time before the guests begin to panic.

When a man is found dead after an excursion. The death is ruled accidental.
Emma begins to suspect that maybe the entire crew is keeping a deadly secret.
Could they all be complicit in the crimes?

Nothing is adding up, and the mystery intensifies.
The only thing Emma is certain of is that The Girl in Her Cabin never saw it coming...