Hot and Cold

When you are born, you get a shiny necklace around your neck. For girls, the necklace gets hotter as they come close to finding their soulmate, but for boys it gets colder. You never fall in love with anyone but your soulmate, never consider anyone else. One day, River Grace feels something burning on her chest. It's the necklace. She doesn't know who her soulmate is, but she's determined to find him. At the same time, a boy named Luke is dealing with the same problem. They crossed paths once, and now Luke won't leave River alone until she helps him, and in return, he helps her. But, what happens if they start to fall in love, even if they may not be soulmates?