In the near future, a scientific development is changing the way people have relationships. People no longer find their own spouses; they're assigned them by the government using an AI program meant to create optimal happiness. The assignments happen at age 18, and Delphine "Del" Everett doesn't want any part of it. She's in love with her boyfriend Tobias and wants to stay with him. But she's legally required to fill out an application explaining what she wants in a partner. She tries to tailor her application so that she'll get assigned to Tobias, and he does the same with his. When their plan doesn't work, Delphine is determined to make her relationship with her new partner, Jasper, fail. But she soon finds her future hangs in the balance between matters of the heart, and the science that claims to have all the answers.