Ernie, Tod, and Sandy Devlin are siblings
whose parents have been deceased for quite some time, and are
part of a motorcycle daredevil act with a traveling circus. Ernie
is the oldest sibling and is the main attraction to the act. Tod,
who is about a year younger, is the main mechanic and driver of
their RV. While Sandy, a high school freshman, is assistant mechanic
who also occasionally joins Ernie on the back of his bike after
one of his stunts, and also is learning a lot about life from
her older brothers. It also seems that in every place the circus
performs, a mystery is in need of solving, and it ends up being
up to the Devlins to solve it.