Max and Maddy are on the trail of a criminal who'll stop at nothing to sabotage Mr Helium's trans-American hot air balloon race.
The prize is a gold balloon worth one million and one dollars, and all the money raised by the race is to go towards the Home for Children Whose Parents Have Disappeared in Balloons—so there's a lot at stake!
Will the detectives be able to blow the dastardly villain's plot sky high?
