He has ten minutes to convince her to stay... and he can keep trying if he fails.
The love of Chris's life walked out on him exactly one year ago. Unable to get over her, he'll use a time machine to go back to then and spend the ten minutes he has to try and stop her from walking out. Discovering that he just can't solve all of their problems in one fell swoop, he'll keep going back to try and figure out what went wrong... and if he can fix it.
