When Rachel invites her new friend Mary over for dinner, the evening takes an unexpected turn. As soon as Mary sees Rachel’s husband, she flies into a rage and makes a shocking accusation. Stunned and caught between her friend and her husband, Rachel’s perfect life begins to unravel.

On paper, Dan and I are that annoyingly perfect suburban family, you know. I’m a marketing director, Dan is a successful software developer, and we live with our precious four-year-old son, Ethan, in one of those houses with manicured lawns and neighborhood barbecues.

But lately, I’d been feeling like I was missing something, even though I didn’t know what. So I did what any self-respecting millennial does when facing an existential crisis: I signed up for a fitness class.

And there I met Mary.

Mary was different. In a good way. She was our instructor, all toned muscles and contagious energy. She was a single mother to a sweet little girl named Cindy. From day one, we clicked.

“Go, Rachel!” she shouted during burpees, grinning like a madwoman. “You can do it! Channel that boardroom boss energy.”

I’d be lying if I said her enthusiasm didn’t terrify me a little at first. But I soon realized I was looking forward to our sessions, and not just for the endorphin rush.

One day after class, while I was sipping water and trying not to pass out, Mary plopped down next to me.

“So,” she said, her eyes sparkling. “Shall we eat tomorrow? There’s a new place downtown that makes amazing salads. And before you say no, remember, we earned this.” And that’s how we got into the groove. Workouts, lunches, shopping trips where we tried on ridiculous outfits and laughed until our sides hurt. It was like going back to college, having a best friend to share everything with. “God, I needed this,” I told her one day over sushi. “Don’t get me wrong, I love my family, but sometimes…”