Grace Lisa Vandenburg counts.

The letters in her name (19). The steps she takes every morning to the local cafe (920); the number of poppy seeds on her slice of orange cake, which dictates the number of bites she’ll take to finish it. Grace counts everything, because numbers hold the world together. And she needs to keep an eye on how they’re doing. Seamus Joseph O'Reilly (also a 19, with the sexiest hands Grace has ever seen) thinks she might be better off without the counting. If she could hold down a job, say. Or open her kitchen cupboards without conducting an inventory, or make a sandwich containing an unknown number of sprouts. Grace’s problem is that Seamus doesn’t count.

Her other problem is… he does.