Recommendations based on "The Secret Seven Collection 1 Books 1-3"

'The Famous Five are off to the Welsh mountains for the holidays, where skiing--and trouble--await. there's something mysterious about the old house near their chalet and the Five plan to investigate. they're soon warned to stay away, but how can they when they suspect someone is trapped inside?' -- Back cover.

'This summer the Five will become six--and George isn't happy about it. American girl Berta has been threatened with kidnap, and Kirrin Cottage is the only place she can hide. But Berta's arrival puts them all in danger when someone starts spying on them from Kirrin Island. Berta may be in disguise, but can they keep her safe and protect her from the kidnappers?' -- Back cover.