In the eigth book of the Calendar Mysteries something special is coming to Green Lawn - a traveling circus! But when the performers arrive, they need help. Their show is a mess, and Bradley, Brian, Nate, and Lucy are happy to chip in. They fix up the equipment and find dazzling new acts, but what the show needs most is an acrobat. No one in town is brave enough to go up on the high trapeze, except for one mysterious masked person. If the kids could find out who it is, this might be the best circus ever - but it seems as if this acrobat doesn't want to be found! -- Amazon.