Lunch just got dangerous.

Josh and Danny don't know it yet but something sinister is waiting in one of their lunchboxes.

One taste and the twins will get ears in their kneecaps and a strange ability to chuck up brown goo - just like a grasshopper. But Petty Potts - the mad scientist from next door-wouldn't let that happen - would she?

Josh and Danny let Petty Potts-their barmy next-door neighbour and scientist extraordinaire-give them a lift to school, but after a mix up with their drink and some S.W.I.T.C.H spray the twins suddenly have green feelers, ears in their abdomens and a strange ability to chuck up brown goo.

The boys must SWITCH back before anyone notices they're not in class. But school is the least of their worries-they're just a whisker away from trouble-there's a grasshopper muncher on the loose . . .

Petty Potts's diary entry:

One day, I am going to find Victor Crouch-confront him-and make him confess that he stole my work and burnt out my memory.

But in the meantime, as far as Josh and Danny are concerned, I will keep my promise and will never make them try any more spray or potion. Or trick them. Or bribe them. Or anything like that. Probably.

Praise for Ali Sparkes's Frozen in Time, winner of the Blue Peter Book of the Year Award

'I know now what they mean by a plot that is toe-curlingly good . . . brilliantly inventive and rollicking fantastical adventure'

Frozen in Time shows [Ali's] skill at fusing traditional children's storytelling with modern tales . . . Sparkes's sci-fi conspiracy thrills will keep 21st-century kids transfixed

It was outstanding. It blew me away

Praise for Wishful Thinking:

A delight from start to finish . . . Sparkes' clear, direct style is easy to read . . . Oh, what fun this is!