A mysterious visitor arrives at Button House with a revelation that leaves Alison reeling. Thomas is equally confused by his feelings for this strange visitor, while Lady Button and Julian warn of sinister motives, and Kitty is as territorial as ever over her surrogate sister Alison. Mike has an epiphany on his first day at a new job, which triggers Julian to remember his first day as a ghost. But will their insights be enough to help Alison make sense of the overwhelming news she has received?

Alison has invited Lucy to come to Button House for a sleepover, but after a concerning meeting with the solicitor, Alison must work out if Lucy is really who she says she is.