What is the main conflict in Numbers: Book 1 by Rachel Ward?

jemma Marsh, known to her friends as Jem, is fifteen years old and living with a foster mom, Karen, when she meets a young black boy named Terry, know to his friends as Spider. Jem initially tries to stay away from Spider because she sees numbers associated with every person with whom she makes eye contact. These numbers represent the date, month and year of that person's death. Jem already knows that Spider is going to die in just a few months. However, Spider is so engaging that Jem finds herself accepting an invitation to his house. There she meets his grandmother, the only family Spider has, who sees auras and immediately recognized Jem as a kindred spirit, though she doesn't initially realize the depth of Jem's gift.