Bell is the youngest member of the underground community that the United States has established on Mars.  Along with four teenagers and six adults, this eleven year-old helps to keep the community going, sharing responsibilities such as growing and harvesting algae and learning about Earth from digital media and the memories of the adults in the settlement.  A curious boy who loves cats, Bell knows that the rules of the community must be followed, the most significant of which is that there can be no contact with any of the other underground settlements established by France, China and Russia.  The settlement’s excitement over the arrival of a shipment of supplies from Earth is soon followed by fear when the adults in the group begin falling deathly ill.  Bell and the teens don’t know why the no contact rule is in place, but realize they may have to venture out of their isolation in hopes of getting the help they need.  Will breaking the rules save the settlement or be the decision that dooms it to perish?  This blend of science fiction and humanistic fiction from a Newbery author is a must read for readers of all ages!