In an alternate world, when people come of age, they enter their DNA into a database called the -gnet. From there they can be matched with people who are genetically compatible. Crowned Princesses Victoria-Margaret is going to Canada for her debut under the guise of Margaret Sandwich. Helena has been invited to the same sebut because of her mother’s work as a placement geneticist. August has an agreement with Helena to marry her, and is invited to the debut to dance with her. Over the summer, the three bond and grapple with secrets that affect their relationships and who they think they are. The aftermath changes their world.
Asexuality isn’t explicitly mentioned or given an allusion. The closest mention is where toward the end Margaret states that she didn’t particularly like the idea of sex until she met Helena. August is given a little bit of potential ace coating toward the end as well where he struggles with his feelings for Helena saying it’s not simple. He also has a line where he says he doesn’t think he’ll ever feel lust for Margaret. I read this as him being ace with a romantic attraction towards Helena, but there can be argued moments of that not being the case with heated kisses happening between August and Helena.