Vivian only has one big regret in life–and a million little ones if you count all the calories she didn’t consume while she was living with the guy who dumped her. But Vivian is glad she moved to Portland with her ex. She’s glad he left her for someone who lives in the city she moved from, because she can now eat her feelings and those feelings taste like wine, tacos, pastries, and gourmet ice cream.

She’s even happy when her newly-engaged sister informs her that she’s hired the toughest personal trainer in town to whip Vivian back into shape for her wedding, because it finally brings her face-to-face with that one big regret—her former best friend from high school.

Brad Mitchell, who claimed she broke his heart and disappeared after they graduated. Who never replied to all those emails about how much she regretted hurting him. The once-chubby, grumpy nerd who was the other person in their two-member book club. The one who now looks infuriatingly hot in a compression tank top and sweatpants.

Brad goes by Mitch these days. He has the same wry sense of humor, a lot of exciting new muscles, and one aggravating, old grudge. But as he puts Vivian through resistance training that tests his own stubborn resolve too, their old spark refuses to die—it just keeps doing more reps.

And those long-ignored emails sitting in Brad’s archived inbox folder? They just might take these former best friends from enemies to lovers and give them the second chance they deserve—if he ever reads them.