Drew is an army brat in West Berlin, where soldiers like his dad hold an outpost of democracy against communist Russia. Drew's cousin Matthias, an East Berliner, has grown up in the wreckage of Allied war bombing, on streets ruled by the secret police.

From enemy sides of this Cold War standoff, the boys become wary friends, arguing over the space race, politics, even civil rights, but bonding over music. If informants catch Matthias with rock 'n' roll records or books Drew has given him, he could be sent to a work camp. If Drew gets too close to an East Berliner, others on the army post may question his family's loyalty. As the political conflict around them grows dire, Drew and Matthias are tested in ways that will change their lives forever.

Set in the tumultuous year leading up to the surprise overnight raising of the Berlin Wall in August 1961, and illustrated with dozens of real-life photographs of the time, Walls brings to vivid life a heroic and tragic episode of the Cold War.