Rosemary Watson and Peter McAllister think their future is clear: they're finally heading off for university. They're thinking about finding apartments, picking courses, living like adults.

But what happens when the future becomes the past? While helping Rosemary's brother move into an apartment in Toronto, Peter and Rosemary fall into an underground river and are swept back in time, to Toronto in 1884. It's a struggle to survive and adapt to the alien culture of the late nineteenth century. Peter and Rosemary are forced to work together, to live together, and to become the adults they've only been pretending to be.

As the days stranded turn to weeks, then months, Rosemary and Peter begin to wonder if they're really ready for a future together - and what they will do if they can't get back.

Then someone brings them a watch, powered by a battery, made in Taiwan.