When Port Wenn puts on their annual "Blood Factory," celebrating the gory horror novel set there, Martin must contain his secret debilitating blood phobia when Louisa gets seriously ill and needs his help.

When Martin's parents make a surprise visit, Martin suspects that his father, Robert, who blindsides his sister Sarah with some infuriating news, is experiencing a serious health condition. Also, while trying to avoid the school's forthcoming closure amidst its annual Spirit Week sleepover, Louisa is made acting principal and Martin and Robert must operate together on Mark.