Nanny Mewes takes on triple trouble in Horley, Surrey, as she offers to help parents Sam and Jason and their four-year-old triplets. The lives of parents Sam and Jason are blighted by the daily barrage of tantrums and bad behaviour from their four-year-old triplets Abbey, Chloe and Emma. With the couple in danger of splitting up over how to discipline - dad believes in smacking, while mum firmly disagrees - the family are at breaking point. Nanny Mewes moves into the family home to implement her three-day action plan. When Kathryn's focus quickly shifts from the girls onto Sam and Jason, will her suspicions that the parents are the root of the family's problems prove true?