The Circus of Adventure-------pan macmillan

"Why did Bill have to bring the babyish Gustavus with them on holiday? Jack knows he’ll only be trouble . . .

But when Gustavus is kidnapped, along with Philip, Dinah and Lucy-Ann, Jack and Kiki the parrot bravely set out to rescue them, leading them to a faraway land and the discovery of a plot to kill the King!"