When a historical-documentary team comes to film at Button House, Alison and the ghosts are shocked to discover that the assassination plot they're exploring involves one of their own.

A mysterious visitor arrives at Button House with a revelation that leaves Alison reeling; Mike has an epiphany on his first day at a new job, which causes Julian to remember his first day as a ghost.

While Button House is being fumigated for woodworm, Alison and Mike decide to save some money and camp in the grounds, which sends the ghosts' routines off-kilter.

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

When the ghosts try to sabotage Alison's makeshift therapy session for Kitty, they unwittingly face their own demons; Mike's desire to see the ghosts yields surprising results

While Alison and Mike gear up to make a big investment, the Captain and Kitty work with the other ghosts to solve an unfolding mystery before it's too late.

When they discover a man living in a tent on their grounds, Alison and Mike, with the ghosts' help, learn that they have more to offer this Christmas than they realised.