Dead ends

Dead ends 
by Erin Jade Lange 
Language: English 
New York : Bloomsbury, 2013. 
328 pages ; 22 cm. 
ISBN: 9781619630802 ; 161963080X 
Summary: When Dane, a bully, refuses to hit Billy D because he has Down Syndrome, Billy takes that as a sign of friendship and enlists Dane's help in solving riddles left in an atlas by his missing father, sending the pair on a risky adventure. 
Available: http://www.amazon.com/Dead-Ends-Erin-Jade-Lange/dp/161963080X