parate fact from otherworldly fiction as they set out to find their missing classmate in this action-packed fourth novel of the Charlie Numbers Adventures series.

As his school's resident numbers guy, Charlie Lewis has always thought that if something can't be proven with a math equation, it might as well be myth--which is exactly how he feels about UFOs.

Charlie just can't believe in the existence of aliens without verifiable proof. Not even Janice, who's the smartest kid Charlie knows, can convince him. But when Charlie's classmate Anthem mysteriously disappears after bringing a supposed space rock to show-and-tell, it's up the Whiz Kids to uncover the truth. As Charlie and the gang trace Anthem's steps to his eerily empty house, it soon becomes clear that perhaps Anthem and his father are involved in something much bigger than a lost rock.

From meeting with UFO enthusiasts, sneaking into hidden rooms, and being following by shadowy and dangerous agents, Charlie is finding it more and more difficult to stick to his convictions--because what if aliens do exist?