Luna Lynn faces a crisis as she unwillingly forges a blood spirit contract with a powerful flea, binding their lives together and provoking ridicule from her family. Despite her anger and fear, the flea gains strength and evolves rapidly by feeding on her blood, promising to become unstoppable soon. Luna struggles with the impossibility of breaking the contract while dealing with her family's scorn. The tension escalates when Peter Shelton arrives unexpectedly, demanding to call off his engagement, leaving Luna and the Lynn family’s future hanging in the balance.