When Harry’s sent to stay with his great-aunts at Lagg Hall, he thinks he’s in for a really dull time. But Auntie Florrie, Aunt Bridget and their elderly friends aren’t quite as Harry expects them to be.

Aren’t they too old to be driving fast cars and climbing trees? And what exactly are the plans they’re making late at night when Harry’s in bed? Plans they don’t want Harry to find out about . . . plans for something no one could call dull . . .