A romantic adventure across the ocean turns into a struggle for survive. After the couple, Tami Oldham and Richard Sharp, go through the ocean they exposed to a very strong hurricane which is considered as one of the strongest hurricanes over the history. They have to face a series of difficulties to get out from there alive.
It's worth noting, too, that while the particulars are easily found via a Google search, given the slim nature of the story, the less one knows going into the movie -- other than the fact that Tami lived to write a book about it -- the better.
Adrift is enough of a boilerplate piece of survival drama that you know to expect those beats more or less coming on schedule, but Woodley makes it more emotionally satisfying than it would be otherwise.
Most of all, Adrift mounts a timely, quiet, stirring statement about our place in the environment, which is at once beautiful, terrifying and utterly indifferent to us, whether we are in the comfort of a population centre or alone amidst its vastness.