Five Go to Billycock Hill (Book 16)
The five are excited to befriend a pilot on holiday. But when he disappears with top-secret equipment, they begin to wonder if he could be a spy ....

Five Go to Billycock Hill (Book 16)
The five are excited to befriend a pilot on holiday. But when he disappears with top-secret equipment, they begin to wonder if he could be a spy . . .

Five Get Into a Fix (Book 17)
On a wonderful skiing holiday, the Five spot a seemingly deserted house. But why do they then see a face in the window? And why does it look so terrified?

Five on Finniston Farm (Book 18)
When they hear that the farm where they're staying has hidden dungeons, the Five can't resist seeking them out. Could they be hiding a dark secret?