For Serena Otaki, free-spirited Californian, life is simple. She loves smashing atoms at The Large Hadron Collider near Geneva, Switzerland. She loves Star Trek, spicy tofu, and her cat, Captain Purrk. She loves her messy (slob-fest) apartment, her chaotic brand of organizing, and staying permanently, happily unattached.

Life is perfect. She has one true love—physics.

Loving a man isn’t in her future.

For Henry Joule, uptight Brit, life is simple. He loves making analog black holes, drinking piping hot tea, and organizing his pencil tray. He loves his family, red meat, and obsessively cleaning his spotless apartment.

Life is perfect. He has many loves—physics, family, friends. He can’t wait to find the woman of his dreams.

Love and marriage are in his future.

One perfect night Serena and Henry meet. Sparks fly, particles collide, the universe comes to a halt, and…

It was a mistake.

They’re too different.

It won’t work.

Love isn’t in their future.

Until an electric storm causes an unexpected event at the particle collider and suddenly—they’ve switched.

Serena is in Henry’s body.

Henry is in Serena’s body.

And both life and love are suddenly very, very complicated.