Geoff has forgotten to post a birthday card to his father, so the boys travel to France to deliver it by hand, but they get locked out of Aquila and have to find a way to get past its force field.
When Tom and Geoff are late back from a trip to the moon, Mrs Murray worries that they've run out of air and decides to tell their mothers all about Aquila. Geoff has forgotten to post a birthday card to his father, so the boys travel to France to deliver it by hand, but they get locked out of Aquila and have to find a way to get past its force field.—Phil G